The interior of a refrigerator has a surface area of 5.6 m2 . It is insulated by a 2.3 cm thick material that has a thermal conductivity of 0.0308 J/m · s · ◦ C. The ratio of the heat extracted from the interior to the work done by the motor is 6% of the theoretical maximum. The temperature of the room is 33.2 ◦C, and the temperature inside the refrigerator is 7.2 ◦C. Determine the power required to run the compressor. Answer in units of W.

Two distinct systems have the same amount of stored internal energy. Assume 500 J are added by heat to the first system, and 300 J are added by heat to the second system. What will be the change in internal energy of the first system if it does 200 J of work? How much work will the second system have to do in order to have the same internal energy?

A heat pump operates with an outside temperature of –10°C and an inside temperature of +19°C. If the building requires 1.6 GJ of heat per day, what is the average power requirement in kW for the heat pump?

You have a spherical heater, outside diameter = 3.40 cm, immersed in a container of water. In order to keep the water in the container heated to a constant temperature of 35.0°C you adjust the temperature of the spherical heater. You reach a steady-state condition when the surface temperature of the spherical heater is at 79.0°C. Assuming the electrical efficiency of the heater is 100.0%, calculate the power required by the heater (i.e., calculate q). Ignore radiation.

You design an engine that takes in 1.50x104 J of heat at 650 K in each cycle and rejects heat at a temperature of 290 K. The engine completes 240 cycles in 1 minute. What is the theoretical maximum power output of your engine, in horsepower? 1 Watt = 1 Joule/s = 0.00134102 horsepower 44.5 hp 15.0 hp 6.50 hp 2.90 hp

A container holding 4.20 kg of water at 20.0°C is placed in a freezer that is kept at -20.0°C. The water freezes and comes to thermal equilibrium with the interior of the freezer. What is the minimum amount of electrical energy required by the freezer to do this if it operates between reservoirs at temperatures of 20.0°C and –-20.0°C? (Latent heat of fusion of ice = capacity of water = 4186 J/(kg K), specific heat capacity of ice = 2100 J/(kg K)). 333,700 J/ kg, specific heat kJ

A gasoline engine takes in 1.61 * 10^4 Jof heat and delivers 3700 J of work per cycle. The heat is obtained byburning gasoline with a heat of combustion of 4.60 * 10^4 J/g. What mass of fuel is burned in each cycle?