You pull hard on both ends of a thick spring, but it does not stretch. Is there an action force and, if so, what is it?
A. no there is no action force
B. yes the action force is the spring resisting to be pulled on
C. yes the action force is the pulling on both ends of the spring

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).