State and explain Newton’s second law of motion.
Newton's second law of motion states that the rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of force.
The law can be divided into two parts:
(i) Rate of change of momentum is directly proportional to the applied force. Larger the force acting on a body, greater is the change in its momentum. Change in momentum is equal to the product of mass and the change in velocity. Mass of the body remains constant. Therefore, rate of change of momentum is directly proportional to the rate of change of velocity i.e., acceleration.
So, Force is directly proportional to mass and acceleration.
(ii) The change of momentum occurs in the direction of the force.
If a body is at rest, a force will set it in motion. If a body is moving with a certain velocity, a force will increase or decrease this velocity accordingly as the force acts in its same or opposite direction.
