Water is pumped from a lake to a storage tank 15 m above at a rate of 60 L/s while consuming 17.5 kW of electric power. Disregarding any frictional losses in the pipes and any changes in kinetic energy, determine the overall efficiency of the pump-motor unit' Disregarding any frictional losses in the pipes and any changes in kinetic energy, determine

a) the overall efficiency of the pump motor unit and
b) the pressure difference between the inlet and the exit of the pump.

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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.