Hi, here's my problem: A 5 kg ball moving right at a velocity of 2 m/s on a frictionless table, collides head-on with a stationary 7.5 kg ball. Find the velocities of the balls if the collision is elastic.(adsbygoogle = window.adsbygoogle || []).push({});

I know you have to use momentum and kinetic energy conservation, then subsitute for one variable, but I don't understand how the equations should be rearranged.

Also, I don't understand how a system can lose kinetic energy without losing momentum, don't they both use the same units (the mass and velocity of the object), so how can one be reduced while the other stays the same?

Thanks for any help

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# Homework Help: Collision Problem help

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