Before heading out on her big date, Ling stands in front of the bathroom mirror brushing her 0.25-m-long hair with a force of 2.0 N. If the crosssectional area of a piece of hair is 1.0 107 m2, by how much does the hair stretch when it is brushed? (Yhair 2.0 109 N)

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)