# Pressure at bottom of oil drum

Gold Member

## Homework Statement

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A vertical cylindrical container contains 5590 gallons of gasoline and is 1.38 m in radius. Due to evaporation within the tank, the pressure on the top of the fluid is 2.5 times normal atmospheric pressure. The density of gasoline is 737 kg/m3

## The Attempt at a Solution

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converted gallons to Liters: 5590 gallons x 3.785L/1 gallon = 21160 L

Found the height of cylinder: Vcylinder = πr2h

21160/(π×1.382) = 3536m

Solve for Pressure using P = Po + ρgh

= (101300 Pa × 2.5) + (737×9.8×3536)

Plugged it all in and it was....wrong. :-/

Only thing I suspect may be wrong is the units I'm suppose to be using ( cm instead of m for example ). Or the possibility of the cylinder being closed when I assumed it was open. But everything else to me looks good. Please help.

Bystander
Homework Helper
Gold Member
Welcome to the concept of "gauge pressure."

gneill
Mentor
converted gallons to Liters: 5590 gallons x 3.785L/1 gallon = 21160 L

Found the height of cylinder: Vcylinder = πr2h

21160/(π×1.382) = 3536m

Solve for Pressure using P = Po + ρgh

= (101300 Pa × 2.5) + (737×9.8×3536)

Plugged it all in and it was....wrong. :-/

Only thing I suspect may be wrong is the units I'm suppose to be using ( cm instead of m for example ). Or the possibility of the cylinder being closed when I assumed it was open. But everything else to me looks good. Please help.
Check the units that you're using for the fluid volume. You want to find a cylinder height in meters and the radius is in meters so the cylinder bottom area is in square meters, so the volume should be given in....

• Bystander