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(ma...

To clarify, KE of the marble is lost through heat for eg. due to this collision being inelastic. If KE of the marble is lost, then how does u(marble) = v(marble)?