Ok here is the problem(adsbygoogle = window.adsbygoogle || []).push({});

A ball with mass M moving horizontally at 5.00 m/s, collides elastically with a block with mass 3M that is initially hanging at rest from the ceiling on the end of a 50.0-cm wire.

Find the maximum angle through which the block swings after it is hit.

Ok what i tried was to see what the velocity of the two objects was when the first object hits the second one.

Mv_{1i}+ 3Mv_{2i}= (4M)v_{f}

the velocity of the hanging object is going to be zero so that whole term cancels out.

i used this equation to find the final velocity, then i used the kenetic energy theorem

.5Mv^{2}+ 3Mgh = 4Mgh to solve for the height that the object swings up. But then i get stuck, because i think its asking me for the angle that the string makes when its at the maximum arc. Am I doing this the right way, if not can someone point me in the right direction.

Thanks

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# Homework Help: Using momentum to find angle

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