a block weighing 2,000 kn is pushed along a surface. a push force of 800 kn is required to just get the block moving and a push force of 600 kn is required to keep the block moving at a constant velocity. determine the coefficient of static friction between the block and the surface. determine the coefficient of kinetic friction between the block and the surface.

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)