EXPLAIN NEWTON'S 2nd LAW

Explanation of Newton's Second Law:

Force on a body is equal to the change in momentum of it.

 Suppose two bodies of different masses are initially at rest, and a fixed force is applied on them for a certain interval of time. To start with, the lighter body picks up a greater speed than the heavier body. However, at the end of the time interval, observation show that each body acquires the same linear momentum. It means that the same force applied for the same time causes the same change in linear momentum in bodies of different masses.

Hence the laws says " When a bigger force is applied on a body of given mass, its linear momentum changes faster and vice-versa. The momentum will change in the direction of the applies force".

Therefore, 

where, Linear momentum of the body, p= mass of the body × velocity of the body.