# linear momentum conservation vs mecanical energy conservation

by jaumzaum
Tags: conservation, energy, linear, mecanical, momentum
 PF Patron P: 243 A ball A (mass ma) with initial velocity v colides with a ball B (mb) initially stopped. A and B gets the same direction/velocity v', Calculate v' By linear momentum conservation ma.v = (ma + mb).v' v' = mav(ma + mb) But by mecanical energy conservation ma.v²/2 = (ma + mb).v'²/2 v' = v (ma/(ma + mb))^(1/2), which is wrong Why we can't use mecanical energy conservation, is there a energy dissipation?
P: 421
 Quote by jaumzaum A ball A (mass ma) with initial velocity v colides with a ball B (mb) initially stopped. A and B gets the same direction/velocity v', Calculate v' ... Why we can't use mecanical energy conservation, is there a energy dissipation?
Well, for A and B to get the same direction/velocity v' after the collision, don't they have to stick?

Does that sound like an elastic collision?

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