Elastic Collisions: Can Objects Move Off Together?

[Shark 774]

Hi guys, just wanted to clear a few things up for myself..

By rearranging the conservation of momentum and conservation of energy equations I think I've shown that a collision that involves the colliding objects moving off together after the collision (like a bullet getting stuck in a pendulum) cannot be elastic. Is this correct?

Thanks.

 

[Doc Al]

Yes, that's correct.