posted by Cheesecake .
I've got a question:
Imagine this scenario where someone releases a marble down an inclined ramp and at the end of the ramp a block is fixed. So the marble will roll down the ramp and it will collide with the block.
Since the block is fixed, m(marble)u(marble) + m(block)u(block) = m(marble)v(marble) + m(block)v(block) by conservation of momentum. Since u(block) and v(block) = 0, u(marble) = v(marble).
Yet, KE of the marble is lost and when it rebounds it will not go back up to its original height. How can momentum be conserved in this case?