# Total pressure of water against submarine

## Homework Statement

What is the total pressure (absolute pressure) against the porthole of a submarine, when the
submarine is at a 35 m depth, and the density of the seawater is 1020 kg/m3. Air pressure is 1
bar and 1 bar = 1×105 Pa. Give the result using unit bar.

Total Pressure

## The Attempt at a Solution

PV=nRT ?

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rock.freak667
Homework Helper

## The Attempt at a Solution

PV=nRT ?
That is for gases.

What is the equation for the pressure given at a certain depth in a fluid? (Hint: The question has most of the relevant quantities that you need in this question)

I don't know the equation, and couldn't get anything from the question..except the difference of pressure.

ah yesyes...maybe P=density*g*height

rock.freak667
Homework Helper

ah yesyes...maybe P=density*g*height
Right that gives the pressure at the depth 'h'. So at depth 'h', you have that pressure acting in addition to what other pressure?

I think the Total pressure would be:
Ptotal=P0+P
Ptotal=105+(1020*9.8*35)
Ptotal=449860 Pa
and that's 4.4986 Bar

rock.freak667
Homework Helper

That should be correct.

Thank you 