Trouble with a basic fluid force problem

[Wyoming Physics]

What is the pressure on a horizontal surface with an area of 2m^2 that is 4m underwater?

I tried to just use the formula: Force= (Density of water)(Area)(Depth)(gravity), plugging in the values Force=(1000kg/m^3)(2m^2)(4m)(9.8m/sec^2) and get 78400 N, when in reality the real answer is supposed to equal 39,200 N/m^2.

 

[mfb]

I can confirm your answer. Maybe someone forgot a factor of 2?

 

[Wyoming Physics]

Ahhh nevermind, I have been calculating the FORCE on the plate and not the PRESSURE on the plate which is P=F/A which would explain they I have to divide the force by 2.

 

[mfb]

Oh, good point. It also changes the units.