Question

A diving bell is to be designed to withstand the pressure of water at a depth of

2000 ft.

a. If sea water weighs 64 lb per cubic foot, what is the pressure at the depth?

b. What is the total force on a circular glass window 6 inches in diameter?

Answer 1

Given:

$h=2000\:\rm ft$

$\rho g=64\:\rm lb/ft^3$

(a)

$$p=\rho g h\\ =64\:{\rm lb/ft^3}*2000\:{\rm ft}\\ =\rm128*10^3\: lb/ft^2=888.9\: lb/in^2$$

(b)

$$F=pA\\ =888.9\:\rm lb/in^2*3.14*(3\: in)^2=25120\: lb$$