4. Michael and his twin brother have a combined mass of 150 kg and are zooming along in a 100 kg amusement park bumper car at 7 m/s. They bump Sarah's car, which is at rest.
Sarah has a mass of 30 kg. After they collide, the twins continue ahead with a speed of 2.5
m/s. How fast is Sarah's car bumped across the floor?
Variables:
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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)