(a) Find the total force on the bottom of a cylindrical gasoline storage tank 15.0 m

high with radius 23.0 m. (b) Find the total force on the side of the tank.

3 answers

find the pressure at the bottom
p = 1 atm + density * g * h
1 atm = about 10^5 pascals or Newtons/m^2

multiply the pressure by the area
F = p A
A = pi r^2

b)
find the pressure halfway up the tank
p = 1 atm + density * g * h/2
multiply that by the total area of the side of the tank
area = 2 pi r h
I suppose that is what they mean. In fact the pressure outward on each side of the tank is always equal and opposite so the net sideways force on the walls of the tank is zero. (it does not move sideways even if there is no friction between the bottom of the tank and the ground:) It would make more sense to ask you what is the tensile stress in the walls of the tank due to the pressure inside.

Thanks

You are welcome.