PDA

View Full Version : Pressure and depth problem


zeronem
Feb3-04, 08:41 PM
I would like someone to tell me the steps for working out this problem. Specifically I would like to know the Equations needed to use for the problem.

Here is the problem. It seems very simple, but I seen to get lost in converting SI Units and then I get confused.

A Piece of wood is 2cm X 4cm X 2mm. It has a density of 450 kg/m/m. To what Depth will it sink in water?

Anyhow, I dont know exactly what to do. I found the Volume in Meters but I have no clue if it is correct. So I then found the mass from the Density and Calculated Volume. I plug the Volume in the Bouyant Force Equation, then I find the Force of weight of the object. What do I do next? Do I find the apparent Force and divide it by Volume? I have no Idea how to find the Depth. I would like a good Explanation as well. Thanks.

kishtik
Feb4-04, 05:12 AM
Is density 450kg/m^3?
We don't know your object's rotation? On which side is it sinking?
Since G=F_b

V_{sunk}d_{fluid}=V_{object}d_{object}

As you will see the volume under water is the same no matter its rotation.