Which statement is true about the gravitational force?
a.
it acts on all objects all of the time.
b.
it only acts on objects that are in contact.
c.
it only acts on objects that are moving apart.
d.
it only acts on objects that are close to each other.

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).