The water that powers the generators enters and leaves the system at a low speed (thus we can neglect its change of kinetic energy) and loses 160 m of altitude during the process. What is the water flow required, in cubic meters per second, to produce this power, assuming 83.5 % efficiency?

Explanation:

Let density of water be ρ .

During flow , volume of water flowing per second is constant

loss of P. E per unit volume  = ρ gh , 83.5 % is lost

Gain of K E per unit volume = 1/2  ρ v²

83.5 % of mgh =   ρ 1/2  ρ v²

1/2  ρ v² =  .835 x 9.8

v² =  2 x .835 x 9.8

= 16.366

v = 4.04 m /s

answer: the answer is a

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.