We recently bought some plants for the back yard. Imagine I created a sled for the plants (total mass of 45.5 kg) and then lowered them down the hill in the backyard allowing gravity to pull them down a 12.8 m long (along the hypotenuse), 19.5 hill. As the sled slides down the hill there is friction (k = 0.275). 

a) How much gravitational potential energy does the sled have at the top of the hill? 

b) How much work would I need to do to lower the sled to the bottom of the hill and bring it to rest? 

c) If it took me 0.650 minutes, what was my average power while lowering it?

d) To do this faster I decide to just release it from rest at the top of the hill and hope that my wife Amy can catch it at the bottom. How fast will the sled be moving when it reaches the bottom of the hill