Motion : An object which changes its position with respect to a fixed point is said to be in motion.  Motion is a relative term : An object at rest with respect to one object may also be in motion with respect to another object.  Reference point : A fixed point with respect to which an object changes its position is known as a reference point.  Distance : The length of actual path between the initial position and the final position of a moving object or body is known as distance travelled by the particle.  Displacement : The shortest distance between the initial and final positions of a moving object or body in a direction from initial to the final position of the particle is known as displacement of the particle.  Units of distance and displacement : SI unit of distance and displacement is metre (m).  Distance travelled by a body is always positive.  Displacement of body may be positive, negative or zero.  Ratio of the magnitude of displacement and the distance is equal to less than 1.  Uniform Motion : The motion of a body is said to be uniform if (i) it moves along a straight line and (ii) it covers equal distance in equal intervals of time, how-so-ever, small these intervals may be.  Non-uniform motion : The motion of a body is said to be non-uniform if it covers unequal distance in equal intervals of time.  Speed : The distance travelled by a body in unit time is known as the speed of the body.  Unit of speed : SI unit of speed is ms–1.  Uniform speed : If a moving body covers equal distances in equal intervals of time, the speed of the body is uniform.  Non-Uniform speed : If a moving body covers unequal distances in equal intervals of time, the speed of the body is non-uniform.  Average speed : The total distance travelled by a body during non-uniform motion divided by the time taken to travel this distance is called average speed. i.e. Average speed =  Velocity : The displacement of the body per unit time is known as the velocity of the body.  Unit of velocity : SI unit of velocity is ms–1.  Uniform velocity : Velocity of a body is said to be uniform velocity if it covers equal displacements in equal intervals of time.  Non-uniform velocity : Velocity of a body is said to be non-uniform if it covers unequal displacement in equal intervals of time.  Speed is a scalar quantity, whereas velocity is a vector quantity.  Speed of a body is always positive.  Velocity of body can be positive as well as negative.  Acceleration : Acceleration of a body is defined as the change in velocity per unit time. i.e.  Positive acceleration : When the velocity of a body increases with time, acceleration of body is said to be positive acceleration. Or When the change in velocity (v) of a body takes place in the direction of the motion of the body, then the acceleration of the body positive.  Negative acceleration or retardation or deceleration : If the velocity of the body decreases with time, then acceleration of body is negative acceleration of retardation. Or When the change in velocity (v) of a body takes place in a direction opposite to the direction of motion of the body, then the acceleration of the body is negative.  S.I. unit of acceleration is m/s2

Motion : An object which changes its position with respect to a fixed point is said to be in motion.  Motion is a relative term : An object at rest with respect to one object may also be in motion with respect to another object.  Reference point : A fixed point with respect to which an object changes its position is known as a reference point.  Distance : The length of actual path between the initial position and the final position of a moving object or body is known as distance travelled by the particle.  Displacement : The shortest distance between the initial and final positions of a moving object or body in a direction from initial to the final position of the particle is known as displacement of the particle.  Units of distance and displacement : SI unit of distance and displacement is metre (m).  Distance travelled by a body is always positive.  Displacement of body may be positive, negative or zero.  Ratio of the magnitude of displacement and the distance is equal to less than 1.  Uniform Motion : The motion of a body is said to be uniform if (i) it moves along a straight line and (ii) it covers equal distance in equal intervals of time, how-so-ever, small these intervals may be.  Non-uniform motion : The motion of a body is said to be non-uniform if it covers unequal distance in equal intervals of time.  Speed : The distance travelled by a body in unit time is known as the speed of the body. That is  Unit of speed : SI unit of speed is ms–1.  Uniform speed : If a moving body covers equal distances in equal intervals of time, the speed of the body is uniform.  Non-Uniform speed : If a moving body covers unequal distances in equal intervals of time, the speed of the body is non-uniform.  Average speed : The total distance travelled by a body during non-uniform motion divided by the time taken to travel this distance is called average speed. i.e. Average speed =  Velocity : The displacement of the body per unit time is known as the velocity of the body.  Unit of velocity : SI unit of velocity is ms–1.  Uniform velocity : Velocity of a body is said to be uniform velocity if it covers equal displacements in equal intervals of time.  Non-uniform velocity : Velocity of a body is said to be non-uniform if it covers unequal displacement in equal intervals of time.  Speed is a scalar quantity, whereas velocity is a vector quantity.  Speed of a body is always positive.  Velocity of body can be positive as well as negative.  Acceleration : Acceleration of a body is defined as the change in velocity per unit time. i.e.  Positive acceleration : When the velocity of a body increases with time, acceleration of body is said to be positive acceleration. Or When the change in velocity (v) of a body takes place in the direction of the motion of the body, then the acceleration of the body positive.  Negative acceleration or retardation or deceleration : If the velocity of the body decreases with time, then acceleration of body is negative acceleration of retardation. Or When the change in velocity (v) of a body takes place in a direction opposite to the direction of motion of the body, then the acceleration of the body is negative.  S.I. unit of acceleration is m/s2

Motion : An object which changes its position with respect to a fixed point is said to be in motion.  Motion is a relative term : An object at rest with respect to one object may also be in motion with respect to another object.  Reference point : A fixed point with respect to which an object changes its position is known as a reference point.  Distance : The length of actual path between the initial position and the final position of a moving object or body is known as distance travelled by the particle.  Displacement : The shortest distance between the initial and final positions of a moving object or body in a direction from initial to the final position of the particle is known as displacement of the particle.  Units of distance and displacement : SI unit of distance and displacement is metre (m).  Distance travelled by a body is always positive.  Displacement of body may be positive, negative or zero.  Ratio of the magnitude of displacement and the distance is equal to less than 1.  Uniform Motion : The motion of a body is said to be uniform if (i) it moves along a straight line and (ii) it covers equal distance in equal intervals of time, how-so-ever, small these intervals may be.  Non-uniform motion : The motion of a body is said to be non-uniform if it covers unequal distance in equal intervals of time.  Speed : The distance travelled by a body in unit time is known as the speed of the body. That is  Unit of speed : SI unit of speed is ms–1.  Uniform speed : If a moving body covers equal distances in equal intervals of time, the speed of the body is uniform.  Non-Uniform speed : If a moving body covers unequal distances in equal intervals of time, the speed of the body is non-uniform.  Average speed : The total distance travelled by a body during non-uniform motion divided by the time taken to travel this distance is called average speed. i.e. Average speed =  Velocity : The displacement of the body per unit time is known as the velocity of the body.  Unit of velocity : SI unit of velocity is ms–1.  Uniform velocity : Velocity of a body is said to be uniform velocity if it covers equal displacements in equal intervals of time.  Non-uniform velocity : Velocity of a body is said to be non-uniform if it covers unequal displacement in equal intervals of time.  Speed is a scalar quantity, whereas velocity is a vector quantity.  Speed of a body is always positive.  Velocity of body can be positive as well as negative.  Acceleration : Acceleration of a body is defined as the change in velocity per unit time. i.e.  Positive acceleration : When the velocity of a body increases with time, acceleration of body is said to be positive acceleration. Or When the change in velocity (v) of a body takes place in the direction of the motion of the body, then the acceleration of the body positive.  Negative acceleration or retardation or deceleration : If the velocity of the body decreases with time, then acceleration of body is negative acceleration of retardation. Or When the change in velocity (v) of a body takes place in a direction opposite to the direction of motion of the body, then the acceleration of the body is negative.  S.I. unit of acceleration is m/s2

Motion : An object which changes its position with respect to a fixed point is said to be in motion.  Motion is a relative term : An object at rest with respect to one object may also be in motion with respect to another object.  Reference point : A fixed point with respect to which an object changes its position is known as a reference point.  Distance : The length of actual path between the initial position and the final position of a moving object or body is known as distance travelled by the particle.  Displacement : The shortest distance between the initial and final positions of a moving object or body in a direction from initial to the final position of the particle is known as displacement of the particle.  Units of distance and displacement : SI unit of distance and displacement is metre (m).  Distance travelled by a body is always positive.  Displacement of body may be positive, negative or zero.  Ratio of the magnitude of displacement and the distance is equal to less than 1.  Uniform Motion : The motion of a body is said to be uniform if (i) it moves along a straight line and (ii) it covers equal distance in equal intervals of time, how-so-ever, small these intervals may be.  Non-uniform motion : The motion of a body is said to be non-uniform if it covers unequal distance in equal intervals of time.  Speed : The distance travelled by a body in unit time is known as the speed of the body. That is  Unit of speed : SI unit of speed is ms–1.  Uniform speed : If a moving body covers equal distances in equal intervals of time, the speed of the body is uniform.  Non-Uniform speed : If a moving body covers unequal distances in equal intervals of time, the speed of the body is non-uniform.  Average speed : The total distance travelled by a body during non-uniform motion divided by the time taken to travel this distance is called average speed. i.e. Average speed =  Velocity : The displacement of the body per unit time is known as the velocity of the body.  Unit of velocity : SI unit of velocity is ms–1.  Uniform velocity : Velocity of a body is said to be uniform velocity if it covers equal displacements in equal intervals of time.  Non-uniform velocity : Velocity of a body is said to be non-uniform if it covers unequal displacement in equal intervals of time.  Speed is a scalar quantity, whereas velocity is a vector quantity.  Speed of a body is always positive.  Velocity of body can be positive as well as negative.  Acceleration : Acceleration of a body is defined as the change in velocity per unit time. i.e.  Positive acceleration : When the velocity of a body increases with time, acceleration of body is said to be positive acceleration. Or When the change in velocity (v) of a body takes place in the direction of the motion of the body, then the acceleration of the body positive.  Negative acceleration or retardation or deceleration : If the velocity of the body decreases with time, then acceleration of body is negative acceleration of retardation. Or When the change in velocity (v) of a body takes place in a direction opposite to the direction of motion of the body, then the acceleration of the body is negative.  S.I. unit of acceleration is m/s2

Motion : An object which changes its position with respect to a fixed point is said to be in motion.  Motion is a relative term : An object at rest with respect to one object may also be in motion with respect to another object.  Reference point : A fixed point with respect to which an object changes its position is known as a reference point.  Distance : The length of actual path between the initial position and the final position of a moving object or body is known as distance travelled by the particle.  Displacement : The shortest distance between the initial and final positions of a moving object or body in a direction from initial to the final position of the particle is known as displacement of the particle.  Units of distance and displacement : SI unit of distance and displacement is metre (m).  Distance travelled by a body is always positive.  Displacement of body may be positive, negative or zero.  Ratio of the magnitude of displacement and the distance is equal to less than 1.  Uniform Motion : The motion of a body is said to be uniform if (i) it moves along a straight line and (ii) it covers equal distance in equal intervals of time, how-so-ever, small these intervals may be.  Non-uniform motion : The motion of a body is said to be non-uniform if it covers unequal distance in equal intervals of time.  Speed : The distance travelled by a body in unit time is known as the speed of the body. That is  Unit of speed : SI unit of speed is ms–1.  Uniform speed : If a moving body covers equal distances in equal intervals of time, the speed of the body is uniform.  Non-Uniform speed : If a moving body covers unequal distances in equal intervals of time, the speed of the body is non-uniform.  Average speed : The total distance travelled by a body during non-uniform motion divided by the time taken to travel this distance is called average speed. i.e. Average speed =  Velocity : The displacement of the body per unit time is known as the velocity of the body.  Unit of velocity : SI unit of velocity is ms–1.  Uniform velocity : Velocity of a body is said to be uniform velocity if it covers equal displacements in equal intervals of time.  Non-uniform velocity : Velocity of a body is said to be non-uniform if it covers unequal displacement in equal intervals of time.  Speed is a scalar quantity, whereas velocity is a vector quantity.  Speed of a body is always positive.  Velocity of body can be positive as well as negative.  Acceleration : Acceleration of a body is defined as the change in velocity per unit time. i.e.  Positive acceleration : When the velocity of a body increases with time, acceleration of body is said to be positive acceleration. Or When the change in velocity (v) of a body takes place in the direction of the motion of the body, then the acceleration of the body positive.  Negative acceleration or retardation or deceleration : If the velocity of the body decreases with time, then acceleration of body is negative acceleration of retardation. Or When the change in velocity (v) of a body takes place in a direction opposite to the direction of motion of the body, then the acceleration of the body is negative.  S.I. unit of acceleration is m/s2

Motion : An object which changes its position with respect to a fixed point is said to be in motion.  Motion is a relative term : An object at rest with respect to one object may also be in motion with respect to another object.  Reference point : A fixed point with respect to which an object changes its position is known as a reference point.  Distance : The length of actual path between the initial position and the final position of a moving object or body is known as distance travelled by the particle.  Displacement : The shortest distance between the initial and final positions of a moving object or body in a direction from initial to the final position of the particle is known as displacement of the particle.  Units of distance and displacement : SI unit of distance and displacement is metre (m).  Distance travelled by a body is always positive.  Displacement of body may be positive, negative or zero.  Ratio of the magnitude of displacement and the distance is equal to less than 1.  Uniform Motion : The motion of a body is said to be uniform if (i) it moves along a straight line and (ii) it covers equal distance in equal intervals of time, how-so-ever, small these intervals may be.  Non-uniform motion : The motion of a body is said to be non-uniform if it covers unequal distance in equal intervals of time.  Speed : The distance travelled by a body in unit time is known as the speed of the body. That is  Unit of speed : SI unit of speed is ms–1.  Uniform speed : If a moving body covers equal distances in equal intervals of time, the speed of the body is uniform.  Non-Uniform speed : If a moving body covers unequal distances in equal intervals of time, the speed of the body is non-uniform.  Average speed : The total distance travelled by a body during non-uniform motion divided by the time taken to travel this distance is called average speed. i.e. Average speed =  Velocity : The displacement of the body per unit time is known as the velocity of the body.  Unit of velocity : SI unit of velocity is ms–1.  Uniform velocity : Velocity of a body is said to be uniform velocity if it covers equal displacements in equal intervals of time.  Non-uniform velocity : Velocity of a body is said to be non-uniform if it covers unequal displacement in equal intervals of time.  Speed is a scalar quantity, whereas velocity is a vector quantity.  Speed of a body is always positive.  Velocity of body can be positive as well as negative.  Acceleration : Acceleration of a body is defined as the change in velocity per unit time. i.e.  Positive acceleration : When the velocity of a body increases with time, acceleration of body is said to be positive acceleration. Or When the change in velocity (v) of a body takes place in the direction of the motion of the body, then the acceleration of the body positive.  Negative acceleration or retardation or deceleration : If the velocity of the body decreases with time, then acceleration of body is negative acceleration of retardation. Or When the change in velocity (v) of a body takes place in a direction opposite to the direction of motion of the body, then the acceleration of the body is negative.  S.I. unit of acceleration is m/s2

Force and Laws of Motion This chapter explains the definition of force, its properties, characteristics, the various laws of motion with statements and explanations followed by examples, exercises, and solved problems for better understanding.

Force and Laws of Motion This chapter explains the definition of force, its properties, characteristics, the various laws of motion with statements and explanations followed by examples, exercises, and solved problems for better understanding.

Gravitation The universal law of gravitation, free fall, acceleration due to gravity, definition, and difference between mass and weight are explained here along with examples for deeper and thorough understanding.

Gravitation The universal law of gravitation, free fall, acceleration due to gravity, definition, and difference between mass and weight are explained here along with examples for deeper and thorough understanding.

Gravitation The universal law of gravitation, free fall, acceleration due to gravity, definition, and difference between mass and weight are explained here along with examples for deeper and thorough understanding.

Motion : An object which changes its position with respect to a fixed point is said to be in motion.  Motion is a relative term : An object at rest with respect to one object may also be in motion with respect to another object.  Reference point : A fixed point with respect to which an object changes its position is known as a reference point.  Distance : The length of actual path between the initial position and the final position of a moving object or body is known as distance travelled by the particle.  Displacement : The shortest distance between the initial and final positions of a moving object or body in a direction from initial to the final position of the particle is known as displacement of the particle.  Units of distance and displacement : SI unit of distance and displacement is metre (m).  Distance travelled by a body is always positive.  Displacement of body may be positive, negative or zero.  Ratio of the magnitude of displacement and the distance is equal to less than 1.  Uniform Motion : The motion of a body is said to be uniform if (i) it moves along a straight line and (ii) it covers equal distance in equal intervals of time, how-so-ever, small these intervals may be.  Non-uniform motion : The motion of a body is said to be non-uniform if it covers unequal distance in equal intervals of time.  Speed : The distance travelled by a body in unit time is known as the speed of the body. That is  Unit of speed : SI unit of speed is ms–1.  Uniform speed : If a moving body covers equal distances in equal intervals of time, the speed of the body is uniform.  Non-Uniform speed : If a moving body covers unequal distances in equal intervals of time, the speed of the body is non-uniform.  Average speed : The total distance travelled by a body during non-uniform motion divided by the time taken to travel this distance is called average speed. i.e. Average speed =  Velocity : The displacement of the body per unit time is known as the velocity of the body.  Unit of velocity : SI unit of velocity is ms–1.  Uniform velocity : Velocity of a body is said to be uniform velocity if it covers equal displacements in equal intervals of time.  Non-uniform velocity : Velocity of a body is said to be non-uniform if it covers unequal displacement in equal intervals of time.  Speed is a scalar quantity, whereas velocity is a vector quantity.  Speed of a body is always positive.  Velocity of body can be positive as well as negative.  Acceleration : Acceleration of a body is defined as the change in velocity per unit time. i.e.  Positive acceleration : When the velocity of a body increases with time, acceleration of body is said to be positive acceleration. Or When the change in velocity (v) of a body takes place in the direction of the motion of the body, then the acceleration of the body positive.  Negative acceleration or retardation or deceleration : If the velocity of the body decreases with time, then acceleration of body is negative acceleration of retardation. Or When the change in velocity (v) of a body takes place in a direction opposite to the direction of motion of the body, then the acceleration of the body is negative.  S.I. unit of acceleration is m/s2

Motion : An object which changes its position with respect to a fixed point is said to be in motion.  Motion is a relative term : An object at rest with respect to one object may also be in motion with respect to another object.  Reference point : A fixed point with respect to which an object changes its position is known as a reference point.  Distance : The length of actual path between the initial position and the final position of a moving object or body is known as distance travelled by the particle.  Displacement : The shortest distance between the initial and final positions of a moving object or body in a direction from initial to the final position of the particle is known as displacement of the particle.  Units of distance and displacement : SI unit of distance and displacement is metre (m).  Distance travelled by a body is always positive.  Displacement of body may be positive, negative or zero.  Ratio of the magnitude of displacement and the distance is equal to less than 1.  Uniform Motion : The motion of a body is said to be uniform if (i) it moves along a straight line and (ii) it covers equal distance in equal intervals of time, how-so-ever, small these intervals may be.  Non-uniform motion : The motion of a body is said to be non-uniform if it covers unequal distance in equal intervals of time.  Speed : The distance travelled by a body in unit time is known as the speed of the body. That is  Unit of speed : SI unit of speed is ms–1.  Uniform speed : If a moving body covers equal distances in equal intervals of time, the speed of the body is uniform.  Non-Uniform speed : If a moving body covers unequal distances in equal intervals of time, the speed of the body is non-uniform.  Average speed : The total distance travelled by a body during non-uniform motion divided by the time taken to travel this distance is called average speed. i.e. Average speed =  Velocity : The displacement of the body per unit time is known as the velocity of the body.  Unit of velocity : SI unit of velocity is ms–1.  Uniform velocity : Velocity of a body is said to be uniform velocity if it covers equal displacements in equal intervals of time.  Non-uniform velocity : Velocity of a body is said to be non-uniform if it covers unequal displacement in equal intervals of time.  Speed is a scalar quantity, whereas velocity is a vector quantity.  Speed of a body is always positive.  Velocity of body can be positive as well as negative.  Acceleration : Acceleration of a body is defined as the change in velocity per unit time. i.e.  Positive acceleration : When the velocity of a body increases with time, acceleration of body is said to be positive acceleration. Or When the change in velocity (v) of a body takes place in the direction of the motion of the body, then the acceleration of the body positive.  Negative acceleration or retardation or deceleration : If the velocity of the body decreases with time, then acceleration of body is negative acceleration of retardation. Or When the change in velocity (v) of a body takes place in a direction opposite to the direction of motion of the body, then the acceleration of the body is negative.  S.I. unit of acceleration is m/s2

Motion : An object which changes its position with respect to a fixed point is said to be in motion.  Motion is a relative term : An object at rest with respect to one object may also be in motion with respect to another object.  Reference point : A fixed point with respect to which an object changes its position is known as a reference point.  Distance : The length of actual path between the initial position and the final position of a moving object or body is known as distance travelled by the particle.  Displacement : The shortest distance between the initial and final positions of a moving object or body in a direction from initial to the final position of the particle is known as displacement of the particle.  Units of distance and displacement : SI unit of distance and displacement is metre (m).  Distance travelled by a body is always positive.  Displacement of body may be positive, negative or zero.  Ratio of the magnitude of displacement and the distance is equal to less than 1.  Uniform Motion : The motion of a body is said to be uniform if (i) it moves along a straight line and (ii) it covers equal distance in equal intervals of time, how-so-ever, small these intervals may be.  Non-uniform motion : The motion of a body is said to be non-uniform if it covers unequal distance in equal intervals of time.  Speed : The distance travelled by a body in unit time is known as the speed of the body. That is  Unit of speed : SI unit of speed is ms–1.  Uniform speed : If a moving body covers equal distances in equal intervals of time, the speed of the body is uniform.  Non-Uniform speed : If a moving body covers unequal distances in equal intervals of time, the speed of the body is non-uniform.  Average speed : The total distance travelled by a body during non-uniform motion divided by the time taken to travel this distance is called average speed. i.e. Average speed =  Velocity : The displacement of the body per unit time is known as the velocity of the body.  Unit of velocity : SI unit of velocity is ms–1.  Uniform velocity : Velocity of a body is said to be uniform velocity if it covers equal displacements in equal intervals of time.  Non-uniform velocity : Velocity of a body is said to be non-uniform if it covers unequal displacement in equal intervals of time.  Speed is a scalar quantity, whereas velocity is a vector quantity.  Speed of a body is always positive.  Velocity of body can be positive as well as negative.  Acceleration : Acceleration of a body is defined as the change in velocity per unit time. i.e.  Positive acceleration : When the velocity of a body increases with time, acceleration of body is said to be positive acceleration. Or When the change in velocity (v) of a body takes place in the direction of the motion of the body, then the acceleration of the body positive.  Negative acceleration or retardation or deceleration : If the velocity of the body decreases with time, then acceleration of body is negative acceleration of retardation. Or When the change in velocity (v) of a body takes place in a direction opposite to the direction of motion of the body, then the acceleration of the body is negative.  S.I. unit of acceleration is m/s2

Motion : An object which changes its position with respect to a fixed point is said to be in motion.  Motion is a relative term : An object at rest with respect to one object may also be in motion with respect to another object.  Reference point : A fixed point with respect to which an object changes its position is known as a reference point.  Distance : The length of actual path between the initial position and the final position of a moving object or body is known as distance travelled by the particle.  Displacement : The shortest distance between the initial and final positions of a moving object or body in a direction from initial to the final position of the particle is known as displacement of the particle.  Units of distance and displacement : SI unit of distance and displacement is metre (m).  Distance travelled by a body is always positive.  Displacement of body may be positive, negative or zero.  Ratio of the magnitude of displacement and the distance is equal to less than 1.  Uniform Motion : The motion of a body is said to be uniform if (i) it moves along a straight line and (ii) it covers equal distance in equal intervals of time, how-so-ever, small these intervals may be.  Non-uniform motion : The motion of a body is said to be non-uniform if it covers unequal distance in equal intervals of time.  Speed : The distance travelled by a body in unit time is known as the speed of the body. That is  Unit of speed : SI unit of speed is ms–1.  Uniform speed : If a moving body covers equal distances in equal intervals of time, the speed of the body is uniform.  Non-Uniform speed : If a moving body covers unequal distances in equal intervals of time, the speed of the body is non-uniform.  Average speed : The total distance travelled by a body during non-uniform motion divided by the time taken to travel this distance is called average speed. i.e. Average speed =  Velocity : The displacement of the body per unit time is known as the velocity of the body.  Unit of velocity : SI unit of velocity is ms–1.  Uniform velocity : Velocity of a body is said to be uniform velocity if it covers equal displacements in equal intervals of time.  Non-uniform velocity : Velocity of a body is said to be non-uniform if it covers unequal displacement in equal intervals of time.  Speed is a scalar quantity, whereas velocity is a vector quantity.  Speed of a body is always positive.  Velocity of body can be positive as well as negative.  Acceleration : Acceleration of a body is defined as the change in velocity per unit time. i.e.  Positive acceleration : When the velocity of a body increases with time, acceleration of body is said to be positive acceleration. Or When the change in velocity (v) of a body takes place in the direction of the motion of the body, then the acceleration of the body positive.  Negative acceleration or retardation or deceleration : If the velocity of the body decreases with time, then acceleration of body is negative acceleration of retardation. Or When the change in velocity (v) of a body takes place in a direction opposite to the direction of motion of the body, then the acceleration of the body is negative.  S.I. unit of acceleration is m/s2

Newton's Law of Motion

Newton's Law of Motion

1. The force of attraction between two bodies in the universe is known as gravitational force. 2. Gravitational force between two bodies of masses m1 and m2 separated by a distance r is given by F = 3. G = 6.673 × 10–11 Nm2 kg–2 is gravitational constant. 4. Gravitational force is large if masses of two bodies are very large. 5. Gravitational force of the earth on a body is known as gravity. 6. The fall of a body is known as free fall if it falls only under the action of gravitational force of earth in the absence of air resistance. 7. Acceleration with which a body falls towards the earth, the gravitational force of the earth is called acceleration due to gravity. It is denoted by 'g'. 8. In S.I., unit of 'g' is m s–2. 9. g = , where M is the mass of the earth and R is the radius of the earth. 10. The value of 'g' on the surface of the earth is 9.8 m s–2. 11. The value of 'g' on the surface of the moon = 1/6 times value of 'g' on the surface of the earth. 12. The value of 'g' decreases with height and depth from surface of the earth. 13. The value of 'g' at poles is more than at equator. 14. The value of 'g' is zero at the centre of the earth. 15. Mass is the quantity of matter contained in a body. 16. In S.I. unit of mass is kg. 17. Weight of a body is the force with which the earth attracts the body. Weight of body always acts at its centre of gravity and in the downward direction, W = mg. 18. In S.I., unit of weight is newton (N). 19. Mass of a body does not change but weight of a body is different at different places.

1. The force of attraction between two bodies in the universe is known as gravitational force. 2. Gravitational force between two bodies of masses m1 and m2 separated by a distance r is given by F = 3. G = 6.673 × 10–11 Nm2 kg–2 is gravitational constant. 4. Gravitational force is large if masses of two bodies are very large. 5. Gravitational force of the earth on a body is known as gravity. 6. The fall of a body is known as free fall if it falls only under the action of gravitational force of earth in the absence of air resistance. 7. Acceleration with which a body falls towards the earth, the gravitational force of the earth is called acceleration due to gravity. It is denoted by 'g'. 8. In S.I., unit of 'g' is m s–2. 9. g = , where M is the mass of the earth and R is the radius of the earth. 10. The value of 'g' on the surface of the earth is 9.8 m s–2. 11. The value of 'g' on the surface of the moon = 1/6 times value of 'g' on the surface of the earth. 12. The value of 'g' decreases with height and depth from surface of the earth. 13. The value of 'g' at poles is more than at equator. 14. The value of 'g' is zero at the centre of the earth. 15. Mass is the quantity of matter contained in a body. 16. In S.I. unit of mass is kg. 17. Weight of a body is the force with which the earth attracts the body. Weight of body always acts at its centre of gravity and in the downward direction, W = mg. 18. In S.I., unit of weight is newton (N). 19. Mass of a body does not change but weight of a body is different at different places.

1. The force of attraction between two bodies in the universe is known as gravitational force. 2. Gravitational force between two bodies of masses m1 and m2 separated by a distance r is given by F = 3. G = 6.673 × 10–11 Nm2 kg–2 is gravitational constant. 4. Gravitational force is large if masses of two bodies are very large. 5. Gravitational force of the earth on a body is known as gravity. 6. The fall of a body is known as free fall if it falls only under the action of gravitational force of earth in the absence of air resistance. 7. Acceleration with which a body falls towards the earth, the gravitational force of the earth is called acceleration due to gravity. It is denoted by 'g'. 8. In S.I., unit of 'g' is m s–2. 9. g = , where M is the mass of the earth and R is the radius of the earth. 10. The value of 'g' on the surface of the earth is 9.8 m s–2. 11. The value of 'g' on the surface of the moon = 1/6 times value of 'g' on the surface of the earth. 12. The value of 'g' decreases with height and depth from surface of the earth. 13. The value of 'g' at poles is more than at equator. 14. The value of 'g' is zero at the centre of the earth. 15. Mass is the quantity of matter contained in a body. 16. In S.I. unit of mass is kg. 17. Weight of a body is the force with which the earth attracts the body. Weight of body always acts at its centre of gravity and in the downward direction, W = mg. 18. In S.I., unit of weight is newton (N). 19. Mass of a body does not change but weight of a body is different at different places.

• Work done on an object is defined as the magnitude of the force multiplied by the distance moved by the object in the direction of the applied force. The unit of work is joule: 1 joule = 1 newton × 1 metre. • Work done on an object by a force would be zero if the displacement of the object is zero. • An object having capability to do work is said to possess energy. • Energy has the same unit as that of work. • An object in motion possesses what is known as the kinetic • energy of the object. An object of mass, m moving with velocity v has a kinetic energy of 1/2 mv2 • The energy possessed by a body due to its change in position or shape is called the potential energy. The gravitational potential energy of an object of mass, m raised through a height, h from the earth’s surface is given by m g h. • According to the law of conservation of energy, energy can only be transformed from one form to another; it can neither be created nor destroyed. The total energy before and after the transformation always remains constant. • Energy exists in nature in several forms such as kinetic energy, potential energy, heat energy, chemical energy etc. The sum of the kinetic and potential energies of an object is called its mechanical energy. • Power is defined as the rate of doing work. The SI unit of power is watt. 1 W = 1 J/s. • The energy used in one hour at the rate of 1kW is called 1 kW h

• Work done on an object is defined as the magnitude of the force multiplied by the distance moved by the object in the direction of the applied force. The unit of work is joule: 1 joule = 1 newton × 1 metre. • Work done on an object by a force would be zero if the displacement of the object is zero. • An object having capability to do work is said to possess energy. • Energy has the same unit as that of work. • An object in motion possesses what is known as the kinetic • energy of the object. An object of mass, m moving with velocity v has a kinetic energy of 1/2 mv2 • The energy possessed by a body due to its change in position or shape is called the potential energy. The gravitational potential energy of an object of mass, m raised through a height, h from the earth’s surface is given by m g h. • According to the law of conservation of energy, energy can only be transformed from one form to another; it can neither be created nor destroyed. The total energy before and after the transformation always remains constant. • Energy exists in nature in several forms such as kinetic energy, potential energy, heat energy, chemical energy etc. The sum of the kinetic and potential energies of an object is called its mechanical energy. • Power is defined as the rate of doing work. The SI unit of power is watt. 1 W = 1 J/s. • The energy used in one hour at the rate of 1kW is called 1 kW h

1. Sound : Sound is a form of energy which produces a sensation of hearing in our ears. 2. Source of sound and its propagation : A source of vibration motion of an object is normally a source of sound. 3. Characteristics of the medium required for the propagation of sound: (i) Medium must be elastic so that the medium particles have the tendency to return back to their original positions after the displacement. (ii) Medium must have the inertia so that its particles have the capacity to store the energy. The frictional resistance of the medium should be negligible to minimise the loss of energy in propagation. 4. Types of waves (i) Mechanical waves : A mechanical wave is a periodic disturbance which requires a material medium for its propagation. On the basis of motion of particles the mechanical waves are classified into two parts. (a) Transverse wave (b) Longitudinal wave (a) Transverse wave : When the particles of the medium vibrate in a direction perpendicular to the direction of propagation of the wave, the wave is known as the transverse wave. For example, waves produced in a stretched string. (b) Longitudinal wave : When the particles of the medium vibrate along the direction of propagation of the wave then the wave is known as the longitudinal wave. For example sound wave in air. (ii) Electromagnetic waves : The waves which do not require medium for propagation are called electromagnetic waves these waves can travel through vacuum also. For example, light waves, X-rays. 5. Characteristics of a sound wave Frequency : The number of vibrations per second is called frequency. The unit of frequency is hertz (ii) Amplitude: The maximum displacement of each particle from its mean position is called amplitude. The S.I. unit of amplitude is metre (m). (iii) Time period: The time taken to complete one vibration is called time period. Frequency= 1/(Time period) or v = 1/T (iv) Wavelength: The distance between two nearest (adjacent) crests or troughs of a wave is called its wavelength. (v) Velocity of wave: The distance travelled by a wave in one second is called velocity of the wave (or speed of the wave). The S.I. unit for the velocity of a wave is metres per second (m/s or ms-1). (vi) Pitch : Pitch is the sensation (brain interpretation) of the frequency of an emitted sound and is the characteristic which distinguishes a shrill (or sharp) sound from a grave (or flat) sound. (vii) Loudness : It is a measure of the sound energy reaching the ear per second. 6. Reflection of sound : When sound waves strike a surface, they return back into the same medium. This phenomenon is called reflection. 7. Laws of reflection : Angle of incidence is equal the angle of reflection. The incident wave, the reflected wave and the normal all lie in the same plane. 8. Echo : Phenomenon of hearing back our own sound is called an echo. It is due to successive reflection from the surfaces obstacles of large size. 9. Relation between speed of sound, time of hearing echo and distance of reflection body :If t is the time at which an echo is heard, d is the distance between the source of sound and the reflecting body and v is the speed of sound. The total distance travelled by the sound is 2d. speed of sound, v = 2d/t or d = vt/2 10. Conditions for the formation of Echoes (i) The minimum distance between the source of sound and the reflecting body should be 17.2 metres. (ii) The wavelength of sound should be less than the height of the reflecting body. (iii) The intensity of sound should be sufficient so that it can be heard after reflection. 11. Reverberation : Persistence of sound after its production is stopped, is called reverberation. A short reverberation is desirable in a concert hall (where music is being played) because it gives ‘life’ to sound. Too much reverberation confuses the programmers and must be reduced to reduce reverberation. 12. Range of Hearing : The audible range of sound for human beings extends from about 20 Hz to 20,000 Hz (one Hz = one cycle/s). Sounds of frequencies below 20 Hz are called infrasonic sound or infrasound. Frequencies higher than 20 kHz are called ultrasonic sound or ultra sound. Ultrasound is produced by dolphins. 13. Applications of ultrasound : The ultrasound is commonly used for medical diagnosis and therapy, and also as a surgical tool. It is also used in a wide variety of industrial applications and processes. Some creatures use ultrasound for information exchange and for the detection and location of objects. Also some bats and porpoises are found to use ultrasound for navi gation and to locate food in darkness or at a place where there is inadequate light for vision (method of search is called echolocation). 14. Sonar : SONAR means Sound Navigation Rang-ing. In this sound waves (ultrasonic) are used [microwaves are absorbed by water)]. Sound waves are emitted by a source. These waves travel in water with velocity v. The waves re-flected by targets (like submarine bottom sea) are detected. Uses (i) The SONAR system is used for detecting the presence of unseen underwater objects, such as a submerged submarine, a sunken ship, sea rock or a hidden iceberg, and locating them accurately. (ii) The principle of SONAR is also used in industry of detection of flaws in metal blocks or sheets without damaging them. 15. Human ear : It is a highly sensitive part of the human body which enables us to hear a sound. It converts the pressure variations in air with audiable frequencies into electric signals which travel to the brain via the auditory nerve. The human ear has three main parts. Their auditory functions are as follows: (i) Outer ear : The outer ear is called `pinna’. It collects the sound from the suri-ounding. The collected sound passes through the auditory canal. At the end of the auditory canal there is a thin membrane called the ear drum or tympanic membrane. When compression of the medium produced due to vibration of the object reaches the ear drum, the pressure on the outside of the membrane increases and forces the eardrum inward. Similarly, the eardrum moves outward when a rarefaction reaches. In this way the ear drum vibrates. (ii) Middle ear: The vibrations are amplified several times by three bones (the hammer, anvil and stirrup) in the middle ear which act as levers. The middle ear transmits the amplified pressure variations received from the sound wave to the inner ear. (iii) Inner ear: In the inner ear, the pressure variations are turned into electrical signals by the cochlea. These electrical signals are sent to the brain via the auditory nerve, and the brain interprets them as sound.

1. Sound : Sound is a form of energy which produces a sensation of hearing in our ears. 2. Source of sound and its propagation : A source of vibration motion of an object is normally a source of sound. 3. Characteristics of the medium required for the propagation of sound: (i) Medium must be elastic so that the medium particles have the tendency to return back to their original positions after the displacement. (ii) Medium must have the inertia so that its particles have the capacity to store the energy. The frictional resistance of the medium should be negligible to minimise the loss of energy in propagation. 4. Types of waves (i) Mechanical waves : A mechanical wave is a periodic disturbance which requires a material medium for its propagation. On the basis of motion of particles the mechanical waves are classified into two parts. (a) Transverse wave (b) Longitudinal wave (a) Transverse wave : When the particles of the medium vibrate in a direction perpendicular to the direction of propagation of the wave, the wave is known as the transverse wave. For example, waves produced in a stretched string. (b) Longitudinal wave : When the particles of the medium vibrate along the direction of propagation of the wave then the wave is known as the longitudinal wave. For example sound wave in air. (ii) Electromagnetic waves : The waves which do not require medium for propagation are called electromagnetic waves these waves can travel through vacuum also. For example, light waves, X-rays. 5. Characteristics of a sound wave Frequency : The number of vibrations per second is called frequency. The unit of frequency is hertz (ii) Amplitude: The maximum displacement of each particle from its mean position is called amplitude. The S.I. unit of amplitude is metre (m). (iii) Time period: The time taken to complete one vibration is called time period. Frequency= 1/(Time period) or v = 1/T (iv) Wavelength: The distance between two nearest (adjacent) crests or troughs of a wave is called its wavelength. (v) Velocity of wave: The distance travelled by a wave in one second is called velocity of the wave (or speed of the wave). The S.I. unit for the velocity of a wave is metres per second (m/s or ms-1). (vi) Pitch : Pitch is the sensation (brain interpretation) of the frequency of an emitted sound and is the characteristic which distinguishes a shrill (or sharp) sound from a grave (or flat) sound. (vii) Loudness : It is a measure of the sound energy reaching the ear per second. 6. Reflection of sound : When sound waves strike a surface, they return back into the same medium. This phenomenon is called reflection. 7. Laws of reflection : Angle of incidence is equal the angle of reflection. The incident wave, the reflected wave and the normal all lie in the same plane. 8. Echo : Phenomenon of hearing back our own sound is called an echo. It is due to successive reflection from the surfaces obstacles of large size. 9. Relation between speed of sound, time of hearing echo and distance of reflection body :If t is the time at which an echo is heard, d is the distance between the source of sound and the reflecting body and v is the speed of sound. The total distance travelled by the sound is 2d. speed of sound, v = 2d/t or d = vt/2 10. Conditions for the formation of Echoes (i) The minimum distance between the source of sound and the reflecting body should be 17.2 metres. (ii) The wavelength of sound should be less than the height of the reflecting body. (iii) The intensity of sound should be sufficient so that it can be heard after reflection. 11. Reverberation : Persistence of sound after its production is stopped, is called reverberation. A short reverberation is desirable in a concert hall (where music is being played) because it gives ‘life’ to sound. Too much reverberation confuses the programmers and must be reduced to reduce reverberation. 12. Range of Hearing : The audible range of sound for human beings extends from about 20 Hz to 20,000 Hz (one Hz = one cycle/s). Sounds of frequencies below 20 Hz are called infrasonic sound or infrasound. Frequencies higher than 20 kHz are called ultrasonic sound or ultra sound. Ultrasound is produced by dolphins. 13. Applications of ultrasound : The ultrasound is commonly used for medical diagnosis and therapy, and also as a surgical tool. It is also used in a wide variety of industrial applications and processes. Some creatures use ultrasound for information exchange and for the detection and location of objects. Also some bats and porpoises are found to use ultrasound for navi gation and to locate food in darkness or at a place where there is inadequate light for vision (method of search is called echolocation). 14. Sonar : SONAR means Sound Navigation Rang-ing. In this sound waves (ultrasonic) are used [microwaves are absorbed by water)]. Sound waves are emitted by a source. These waves travel in water with velocity v. The waves re-flected by targets (like submarine bottom sea) are detected. Uses (i) The SONAR system is used for detecting the presence of unseen underwater objects, such as a submerged submarine, a sunken ship, sea rock or a hidden iceberg, and locating them accurately. (ii) The principle of SONAR is also used in industry of detection of flaws in metal blocks or sheets without damaging them. 15. Human ear : It is a highly sensitive part of the human body which enables us to hear a sound. It converts the pressure variations in air with audiable frequencies into electric signals which travel to the brain via the auditory nerve. The human ear has three main parts. Their auditory functions are as follows: (i) Outer ear : The outer ear is called `pinna’. It collects the sound from the suri-ounding. The collected sound passes through the auditory canal. At the end of the auditory canal there is a thin membrane called the ear drum or tympanic membrane. When compression of the medium produced due to vibration of the object reaches the ear drum, the pressure on the outside of the membrane increases and forces the eardrum inward. Similarly, the eardrum moves outward when a rarefaction reaches. In this way the ear drum vibrates. (ii) Middle ear: The vibrations are amplified several times by three bones (the hammer, anvil and stirrup) in the middle ear which act as levers. The middle ear transmits the amplified pressure variations received from the sound wave to the inner ear. (iii) Inner ear: In the inner ear, the pressure variations are turned into electrical signals by the cochlea. These electrical signals are sent to the brain via the auditory nerve, and the brain interprets them as sound.

1. Sound : Sound is a form of energy which produces a sensation of hearing in our ears. 2. Source of sound and its propagation : A source of vibration motion of an object is normally a source of sound. 3. Characteristics of the medium required for the propagation of sound: (i) Medium must be elastic so that the medium particles have the tendency to return back to their original positions after the displacement. (ii) Medium must have the inertia so that its particles have the capacity to store the energy. The frictional resistance of the medium should be negligible to minimise the loss of energy in propagation. 4. Types of waves (i) Mechanical waves : A mechanical wave is a periodic disturbance which requires a material medium for its propagation. On the basis of motion of particles the mechanical waves are classified into two parts. (a) Transverse wave (b) Longitudinal wave (a) Transverse wave : When the particles of the medium vibrate in a direction perpendicular to the direction of propagation of the wave, the wave is known as the transverse wave. For example, waves produced in a stretched string. (b) Longitudinal wave : When the particles of the medium vibrate along the direction of propagation of the wave then the wave is known as the longitudinal wave. For example sound wave in air. (ii) Electromagnetic waves : The waves which do not require medium for propagation are called electromagnetic waves these waves can travel through vacuum also. For example, light waves, X-rays. 5. Characteristics of a sound wave Frequency : The number of vibrations per second is called frequency. The unit of frequency is hertz (ii) Amplitude: The maximum displacement of each particle from its mean position is called amplitude. The S.I. unit of amplitude is metre (m). (iii) Time period: The time taken to complete one vibration is called time period. Frequency= 1/(Time period) or v = 1/T (iv) Wavelength: The distance between two nearest (adjacent) crests or troughs of a wave is called its wavelength. (v) Velocity of wave: The distance travelled by a wave in one second is called velocity of the wave (or speed of the wave). The S.I. unit for the velocity of a wave is metres per second (m/s or ms-1). (vi) Pitch : Pitch is the sensation (brain interpretation) of the frequency of an emitted sound and is the characteristic which distinguishes a shrill (or sharp) sound from a grave (or flat) sound. (vii) Loudness : It is a measure of the sound energy reaching the ear per second. 6. Reflection of sound : When sound waves strike a surface, they return back into the same medium. This phenomenon is called reflection. 7. Laws of reflection : Angle of incidence is equal the angle of reflection. The incident wave, the reflected wave and the normal all lie in the same plane. 8. Echo : Phenomenon of hearing back our own sound is called an echo. It is due to successive reflection from the surfaces obstacles of large size. 9. Relation between speed of sound, time of hearing echo and distance of reflection body :If t is the time at which an echo is heard, d is the distance between the source of sound and the reflecting body and v is the speed of sound. The total distance travelled by the sound is 2d. speed of sound, v = 2d/t or d = vt/2 10. Conditions for the formation of Echoes (i) The minimum distance between the source of sound and the reflecting body should be 17.2 metres. (ii) The wavelength of sound should be less than the height of the reflecting body. (iii) The intensity of sound should be sufficient so that it can be heard after reflection. 11. Reverberation : Persistence of sound after its production is stopped, is called reverberation. A short reverberation is desirable in a concert hall (where music is being played) because it gives ‘life’ to sound. Too much reverberation confuses the programmers and must be reduced to reduce reverberation. 12. Range of Hearing : The audible range of sound for human beings extends from about 20 Hz to 20,000 Hz (one Hz = one cycle/s). Sounds of frequencies below 20 Hz are called infrasonic sound or infrasound. Frequencies higher than 20 kHz are called ultrasonic sound or ultra sound. Ultrasound is produced by dolphins. 13. Applications of ultrasound : The ultrasound is commonly used for medical diagnosis and therapy, and also as a surgical tool. It is also used in a wide variety of industrial applications and processes. Some creatures use ultrasound for information exchange and for the detection and location of objects. Also some bats and porpoises are found to use ultrasound for navi gation and to locate food in darkness or at a place where there is inadequate light for vision (method of search is called echolocation). 14. Sonar : SONAR means Sound Navigation Rang-ing. In this sound waves (ultrasonic) are used [microwaves are absorbed by water)]. Sound waves are emitted by a source. These waves travel in water with velocity v. The waves re-flected by targets (like submarine bottom sea) are detected. Uses (i) The SONAR system is used for detecting the presence of unseen underwater objects, such as a submerged submarine, a sunken ship, sea rock or a hidden iceberg, and locating them accurately. (ii) The principle of SONAR is also used in industry of detection of flaws in metal blocks or sheets without damaging them. 15. Human ear : It is a highly sensitive part of the human body which enables us to hear a sound. It converts the pressure variations in air with audiable frequencies into electric signals which travel to the brain via the auditory nerve. The human ear has three main parts. Their auditory functions are as follows: (i) Outer ear : The outer ear is called `pinna’. It collects the sound from the suri-ounding. The collected sound passes through the auditory canal. At the end of the auditory canal there is a thin membrane called the ear drum or tympanic membrane. When compression of the medium produced due to vibration of the object reaches the ear drum, the pressure on the outside of the membrane increases and forces the eardrum inward. Similarly, the eardrum moves outward when a rarefaction reaches. In this way the ear drum vibrates. (ii) Middle ear: The vibrations are amplified several times by three bones (the hammer, anvil and stirrup) in the middle ear which act as levers. The middle ear transmits the amplified pressure variations received from the sound wave to the inner ear. (iii) Inner ear: In the inner ear, the pressure variations are turned into electrical signals by the cochlea. These electrical signals are sent to the brain via the auditory nerve, and the brain interprets them as sound.

The Fundamental Unit of Life Discovery of the cell, nucleus, cytoplasm, DNA, Chromosomes, Mitochondria, Plastids, chloroplast, reticulum, cell organelles, Golgi, apparatus, leucoplast, vacuoles, Unicellular and Multicellular organisms, etc are a few important topics covered in this chapter.

The Fundamental Unit of Life Discovery of the cell, nucleus, cytoplasm, DNA, Chromosomes, Mitochondria, Plastids, chloroplast, reticulum, cell organelles, Golgi, apparatus, leucoplast, vacuoles, Unicellular and Multicellular organisms, etc are a few important topics covered in this chapter.

The Fundamental Unit of Life Discovery of the cell, nucleus, cytoplasm, DNA, Chromosomes, Mitochondria, Plastids, chloroplast, reticulum, cell organelles, Golgi, apparatus, leucoplast, vacuoles, Unicellular and Multicellular organisms, etc are a few important topics covered in this chapter.

Tissues Starting with the definition of tissue, the two different types of tissues are explained in detail, they are: Plant Tissue Here the definition, importance of plant tissues are explained, along with the two types of plant tissues are discussed here. Meristematic tissues, Permanent tissues, are explained with examples here. Also, terms like Primary Meristems, Secondary Meristems, Apical Meristem, Lateral Meristem, Intercalary Meristem, Simple Permanent Tissue, Parenchyma, Collenchyma, Sclerenchyma, Complex Permanent Tissue, Xylem, Phloem are discussed in detail. Also, tissue systems like Epidermal, Ground, Vascular tissue systems along with secondary growth in plants concept are explained here. Animal Tissue Definition, the importance of animal tissue along with various types like Epithelial, Connective, Muscular, Nervous tissue, Areolar, Adipose, Tendon tissues, Skeletal, Smooth, Cardiac muscles are also explained here with examples and pictorial representation for better understanding.

Why do we fall ill This is a general topic where, the topics like reasons why we fall ill, precautions to be taken to prevent any diseases, and medicines to be taken and proper health care steps, household, and environmental conditions to be followed to stay healthy and fit are few topics discussed here.

Everything in this universe is made up of material which scientists have named “matter”. The air we breathe, the food we eat, stones, clouds, stars, plants and animals, even a small drop of water or a particle of sand — every thing is matter.

Everything in this universe is made up of material which scientists have named “matter”. The air we breathe, the food we eat, stones, clouds, stars, plants and animals, even a small drop of water or a particle of sand — every thing is matter.

Everything in this universe is made up of material which scientists have named “matter”. The air we breathe, the food we eat, stones, clouds, stars, plants and animals, even a small drop of water or a particle of sand — every thing is matter.

A pure substance consists of a single type of particles. In other words, a substance is a pure single form of matter. As we look around, we can see that most of the matter around us exist as mixtures of two or more pure components, for example, sea water, minerals, soil etc.

A pure substance consists of a single type of particles. In other words, a substance is a pure single form of matter. As we look around, we can see that most of the matter around us exist as mixtures of two or more pure components, for example, sea water, minerals, soil etc.

A pure substance consists of a single type of particles. In other words, a substance is a pure single form of matter. As we look around, we can see that most of the matter around us exist as mixtures of two or more pure components, for example, sea water, minerals, soil etc.

A pure substance consists of a single type of particles. In other words, a substance is a pure single form of matter. As we look around, we can see that most of the matter around us exist as mixtures of two or more pure components, for example, sea water, minerals, soil etc.

A tiny particle of a chemical element is called an atom, which may or may not exist independently. Molecules refer to the group of atoms that the bond binds together, representing the smallest unit in a compound.

A tiny particle of a chemical element is called an atom, which may or may not exist independently. Molecules refer to the group of atoms that the bond binds together, representing the smallest unit in a compound.

A tiny particle of a chemical element is called an atom, which may or may not exist independently. Molecules refer to the group of atoms that the bond binds together, representing the smallest unit in a compound.