Question

(a) How high in meters must a column of water be to exert a pressure equal to that of a 760-mm column of mercury? The density of water is 1.0 g/mL, whereas that of mercury is 13.6 g/mL. (b) What is the pressure in atmospheres on the body of a diver if he is 39 ft below the surface of the water when atmospheric pressure at the surface is 0.95 atm?

Answer 1

Pwater = Pmercury

P = density of x * gravity * height of x

Pwater = Pmercury

density of water * gravity * height of water   = density of mercury * gravity * height of mercury

density of water * height of water   = density of mercury * height of mercury

1 g/mL * h water = 13.6 g/mL * 760 mm

h water = 13.6*760/1 mm = 10336 mm of water = 10.336 meters of water

b.

Patm in:

h = 39 ft = 11.88 m

Pwater = D*G*h = 1000*9.8*11.88 = 116424 Pa = 116424/101325 = 1.1490 atm

Ptotal = Patm + Pwater = 0.95 + 1.1490 = 2.099 atm