When a 4-kg ball is thrown upwards at 40 m/s, at what height is the potential energy equal to the kinetic
energy

6–55 refrigerant-134a enters the condenser of a residential heat pump at 800 kpa and 358c at a rate of 0.018 kg/s and leaves at 800 kpa as a saturated liquid. if the compressor consumes 1.2 kw of power, determine (a) the cop of the heat pump and (b) the rate of heat absorption from the outside air.

5. why should the electrons be placed separate from each other (why not together)?

In the absence of friction gravity and all other external forces