A team of sled rides has a mass of 180 kg. If they have 8,000 J of kinetic energy at the bottom of the hill, how tall was the hill they just tackled?
m*g = 180kg * 9.8N/kg = 1764 N.
PE = mg*h = 8000 J @ top of hill.
h = 8000/mg = 8000/1764 = 4.54 m.