Asled and rider with a combined mass of 140 kg are at the top of a hill of height 12.5 m above the level ground below. the sled is given a push providing an initial kinetic energy of 1550 j at the top of the hill. choosing a reference level at the bottom of the hill, what is the potential energy of the sled and rider at the top of the hill?

Refrigerant-134a flows through a carnot heat pump cycle at 0.5 kg/s. it is known that the maximum absolute temperature in the cycle is 1.1 times the minimum absolute temperature, and the net power input to the cycle is 2.5 kw. if the refrigerant changes from a saturated vapor to a saturated liquid during the heat rejection process, determine the maximum magnitude of the enthalpy of vaporization for this process in kj/kg (with 3 significant figures).