A boat has a porthole window, of area 0.00849 m^2, 6.25 m below the surface. The density of sea water is 1027 kg/m^3. The air inside the boat is at 1 atm. What is the net force on the window?

1391.54 N

Explanation:

Area of window, A = 0.00849 m^2

Depth, h = 6.25 m

density of sea water, d = 1027 kg/m^3

Atmospheric pressure, Po = 1 atm = 1.01 x 10^5 Pa

Pressure at window,

P = Po + h d g

P = 1.01 x 10^5 + 6.25 x 1027 x 9.8 = 163903.75 Pa

Force on window = Pressure on window x Area of window

F = 163903.75 x 0.00849 = 1391.54 N