HLP in a tennis match he throws a ball immediately after the service the ball has a speed of 50 m / s in relation to the ground and moves horizontally in a direction 30º to the west of the north the opponent player Rita is running to the south with a speed 6 m / s in relation to the ground. From Rita's point of view, what is the magnitude and direction taking north by reference to the speed of the ball?

Acommercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at -35°c by rejecting waste heat to cooling water that enters the condenser at 18°c at a rate of 0.25 kg/s and leaves at 26°c. the refrigerant enters the condenser at 1.2 mpa and 50°c. if the compressor consumes 3.3 kw of power, determine (a) the mass flow rate of the refrigerant, (b) the refrigeration load, (c) the cop, and (d) the minimum power input to the compressor for the same refrigeration load.