At steady state, a heat pump provides energy by heat transfer at the rate of 25,000 btu/h to maintain a dwelling at 708f on a day when the outside temperature is 308f. the power input to the heat pump is 4.5 hp. determine (a) the coefficient of performance of the heat pump. (b) the coefficient of performance of a reversible heat pump operating between hot and cold reservoirs at 708f and 308f, respectively, and the corresponding rate at which energy would be provided by heat transfer to the dwelling for a power input of 4.5 hp.

Adding more pulleys to a system of pulleys needed to lift an object. a. increases the force b. decreases the force c. increases the amount of work d. decreases the amount of work

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s.part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.

Aproton is shot from the negative disk toward the positive disk. what launch speed must the proton have to just barely reach the positive disk?