Two blocks are placed at the ends of a horizontal massless board, as in the drawing. the board is kept from rotating and rests on a support that serves as an axis of rotation. the block on the right has a mass of 5.8 kg. determine the magnitude of the angular acceleration when the system is allowed to rotate.

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).