- 105

- 3

Now I know that 1 exerts a force on 2, hence doing work, which in turn uses its kinetic energy up. Therefore, 2 speeds up, gaining the work done.

But ball 2 exerts a force on 1, doing negative work, hence taking energy. So I am confused. Doesn't ball 1 exerting a force, doing work, mean it will naturally have less kinetic energy and slow down. If so, then wouldn't ball 2's force in slowing it down be redundant?

What am I missing here? My confusion is that in ball 1 doing work, it is using the kinetic energy, as it speed up ball 2 which should mean it is slowing down. so the reaction force, which I know has to be there, seems redundant but yet I know that it is there.