CBSE Class 9 Answered

Hi dear,

If a group of bodies are exerting force on each other or interacting with each other their total momentum remains conserved before and after the interaction provided there is no external force acting on them.

For example, 

Two balls A and B ( moving in the same direction) say having masses m1 and m2 collide with each other. Let us assume even after collision, they move in the same direction and the collison lasted for very short period t seconds.

A exerts a force on B and B exerts a force on A, Due to the action and rection forces, velocities of A and B changes , but the total momentum of the system remains unchanged which is the conservation of momentum.

P = mv

P is the momentum,m is the mass and v is the velocity  of an object.

Hope this helped.

Regards

Topperlearning.com