A 4-ton air conditioner removes 5.06×107 J (48,000 British thermal units) from a cold environment in 1.00 h. (a) What energy input in joules is necessary to do this if the air conditioner has an energy efficiency rating ( EER ) of 12.0?  (b) What is the cost of doing this if the work costs 10.0 cents per 3.60×106J (one kilowatt-hour)? (c) Discuss whether this cost seems realistic. Note that the energy efficiency rating ( EER ) of an air conditioner or refrigerator is defined to be the number of British thermal units of heat transfer from a cold environment per hour divided by the watts of power input.

A pronghorn antelope can run at a remarkable 18 m/sm/s for up to 10 minutes, almost triple the speed that an elite human runner can maintain. For a 32 kgkg pronghorn, this requires an astonishing 3.4 kWkW of metabolic power, which leads to a significant increase in body temperature. If the pronghorn had no way to exhaust heat to the environment, by how much would its body temperature increase during this run? (In fact, it will lose some heat, so the rise won't be this dramatic, but it will be quite noticeable, requiring adaptations that keep the pronghorn's brain cooler than its body in such circumstances.) Assume the efficiency of the pronghorn to be equal to that of human.

The concrete slab of a basement is 11m long, 8 m wide and 0.2 m thick. During the winter, temperatures are nominally 17°C and 10°C at the top and bottom respectively. If the concrete has thermal conductivity of 1.4 W/m K, what is the rate of heat loss through the slab? If the basement is heated by a gas furnace operating at an efficiency of 90% using natural gas priced at Cg = Php 1.00/MJ, what is the daily cost of heat loss?