I am having a lot of difficulty with this problem:(adsbygoogle = window.adsbygoogle || []).push({});

Consider a frictionless track as shown in Figure P6.48. A block of mass m1 = 4.20 kg is released from A. It makes a head on elastic collision at B with a block of mass m2 = 10.5 kg that is initially at rest. Calculate the maximum height to which m1 rises after the collision.

My plan was to use (KE+PE)i=(KE+PE)f, somehow.

I know that at the time of release block A has 205.8 J of potential energy, from PE=mgy, but I need the final velocity in order to use the conservation equation.

I found the velocity before the collision using (delta y)=.5(Vyo+Vy)t, and got 9.9m/s for Block A, B is at rest.

Then I tried to figure out the velocity after the collision, using (m1v1+m2v2)i = (m1v1+m2v2)f

I had (4.2 x 9.9)= (m1v1+m2v2)f, so m2v2f=41.58-m1v1, and that is where I seem to be stuck, I can't figure out how to carry on or if I am even right up to this point. Any tips are EXTREMELY appreciated!

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# Homework Help: Elastic collision find max height

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