Consider point charges of +q and +4q, which are separated by 3.0 m. at what point, on a linebetween the two charges, would it be possible to place a charge of -q such that the electrostatic force acting on it would be zero?

Which changes would result in a decrease in the gravitational force btween two objects? check all that apply

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)

An object dropped from cliff falls with a constant acceleration of 10 metre per second square find its speed of two seconds after it was dropped