A boy with mass 50kg running at 50m/s homos on a 20 kg trolley traveling at the same direction at 1.5 m/s. What is the common velocity?

What is the average speed of a car that travels 40mph for 1 hour and 60 mph in another hour will mark brainliest

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)

What happens when a rubber rod is rubbed with a piece of fur?