Elastic Collisions: Can Objects Move Off Together?

AI Thread Summary
In elastic collisions, both momentum and kinetic energy are conserved, meaning that the objects rebound off each other without any loss of energy. When two objects move off together after a collision, as in the case of a bullet embedding in a pendulum, kinetic energy is not conserved, indicating that the collision is inelastic. The rearrangement of the conservation equations confirms that such a scenario cannot be elastic. Therefore, if objects move off together post-collision, it is indeed an inelastic collision. This clarification reinforces the fundamental principles of collision types in physics.
Shark 774
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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.
 
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Yes, that's correct.
 

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