A long platform is holding your physics teacher in the air above some hungry alligators. Your physics teacher has a mass of 75 kg and is located 2 m from one end. The 10.0 m platform has a mass of 10.0 kg, and its center of gravity is located 4.0 m from the same end. The platform is being held up by two students, one at either end. a. What force is required by each student to hold the platform up?

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.