8. A block, m = 2.5 kg, slides on a friction-free track and is moving a 4 m/s at point at the top of a hill 6 m high. a) How fast is the block moving at the bottom of the hill? b) Now the block encounters a spring (k = 1000 N/m)at the bottom of the hill. By how much is the spring compressed?

11. Go back to 8. Same block, same hill, same speed at the top. We remove the spring from the bottom of the hill and replace it with a high friction surface where mu = .3. How far does the block slide before coming to rest?

	This is a situation where the block has 147J + 5J = 152J of energy when it arrives at the bottom. By the time the block stops, it has dissipated all of this energy. Where did it go?