8. Rubbing a plastic bag and a balloon with a cloth gives both objects a net negative charge. The balloon's
charge is -1x10^-10 C and the bag's charge is -1x10^-5 C, and each object has a mass of 0.02 grams.
Wearing insulating gloves, you hold the bag above the balloon and let go. How far above the center of the
balloon will the bag 'levitate'?

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)