# what is second law of motion

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## what is second law of motion

Q- State and explain Newton’s second law of motion.

Ans-Newton’s second law of motion. This law states that the rate of change of momentum of a body is directly proportional to the applied unbalanced force and the change takes place in the direction of the force. This law can be divided into two parts:

(i) The rate of change of momentum is directly proportional to the applied force. The larger the force acting on a body, greater is the change in its momentum. Since change in momentum is equal to the product of mass and the change in velocity and the mass of the body remains constant, so the rate of change of momentum is directly proportional to the rate of change of velocity i.e., acceleration. Hence force (F) is directly proportional to mass (m) and F acceleration (a).

F∝ma.

(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.