An echo is a reflection of sound against another surface. Suppose you are standing on one side of a canyon and you yodeled. Suppose the temperature is 20°C and the canyon is 750 m wide, how long does it take for you to hear the echo
of your yodel?

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).