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

the answer for apex is the lowest

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)