Physics problems?

Question

5. If 1 cubic meter of water is at the top of a reservoir. How fast can it be moving if it drops 100 meters to some electric turbines below? The density of water is 100 Kg/m^3)

6. What is the pressure at the depth of 100 meters of water?

Answer 1

5. Volume = 1m^3
Mass of water m = 1m^3*100kg/m^3=100kg

If 100 kg water falls a height of 100 m under gravity then it will acquire kinetic energy which will be equal to loss in its potential energy. The speed with which it reach turbine is to be calculated.

(1/2) m v^2 = mgh so v^2 = 2gh = 2* 9.8* 100

V=44.27 m/s

you can calculate it by this also, u = o at start, moves distance h with acceleration g

v^2 = 0 +2gh
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The hydrostatic pressure P = h*d*g Newton/m^2

where h is the height from the free surface of medium (water) d is density of water (medium) - for air h is measured from from top where our atmosphere starts (P at head is less than at feet in air).
As you go deeper in water P increases.

P = 100 m* 100kg/m^3 * 9.8 m/s^2= 98000 N/m^2