physic
posted by Chan .
Hi! I really need help on Part B only.
(a) Calculate the absolute pressure at the bottom of a freshwater lake at a depth of 28.7 m. Assume the density of the water is 1.00 103 kg/m3 and the air above is at a pressure of 101.3 kPa.
(b) What force is exerted by the water on the window of an underwater vehicle at this depth if the window is circular and has a diameter of 40.9 cm?
So, I try to convert 40.9cm to 0.409*9.8 but, it not right.

Why would you multiply the diameter by g?
Force equals pressure times area.
You are still mispelling the subject.
A "physic" is a laxative. 
40.9cm = 0.409m
diameter/2 = radius
0.409m/2 = 0.2045
area of circle = (pi)r^2
F=PA
F=(what you got for pressure from Part A)((pi)r^2)