# Force of water in a container

1. Jun 15, 2006

### DarkWarrior

Hello everyone, newbie here.. sorry if I posted this in the wrong place.

We just went over fluids today. And I can’t seem to solve a problem that has to do with force due to pressure. The problem is: An open U shaped container is filled with water to the top. What is the force due to the water on side A?

Now pressure = (density)*(gravity)*(height) I believe.
Force is pressure*area. Since side A is a square, that’s simply length squared for area.

So I believe the equation to use in this case is Force = (density)*(gravity)*(height)*(Area).

But for some reason, I keep getting the wrong answer. Here’s a badly drawn picture of the container. Can anyone give me some pointers?

http://img151.imageshack.us/img151/9338/untitled5vd.th.jpg [Broken]

Last edited by a moderator: May 2, 2017
2. Jun 15, 2006

### Staff: Mentor

Since it's an open container, don't forget to include the effect of atmospheric pressure. Otherwise, your thinking is correct (assuming you use the correct height).

3. Jun 15, 2006

### Pyrrhus

Looks ok to me, Maybe you should check your units.

4. Jun 15, 2006

### DarkWarrior

Thank you for the help! Turns out it was atmospheric pressure. You have to add it to the pressure of the water and then multiply by area to get force.

I should read more carefully. :)