What causes friction? A. Inertia
B. Tiny collisions, called microwelds, on surfaces, even those that
seem smooth
C. Action - Reaction
D. All surfaces are rough to the touch and therefore cause friction

What are the factors that affect the resistance of a wire?

According to newtons universal law of gravitation, which would change the parh of the ball so it traces out widest curved path possible?

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)