Questsion involving pressure difference due to submarine diving

1. May 26, 2013

skyturnred

1. The problem statement, all variables and given/known data

A submarine maintains 100 kPa inside it and dives 250 m down in the ocean having an average density of 1030 kg/m$^{3}$. What is the pressure difference between the inside and the outside of the submarine in kPa?

2. Relevant equations

3. The attempt at a solution

I am quite confused by the question. If I was given the ambient pressure just before the dive, I would solve this problem by doing the following:

P$_{ambient}$=P$_{@250m}$-(250m)(9.81m/s$^{2}$)($\rho$)

Then I would simply take the difference of the pressure at this depth and the pressure of the submarine. However, the prof has consistently been providing all necessary pressures and densities for all questions. Also, she has consistently only provided necessary information.

This leads me to believe I need to solve the question using the density of the submarine.

Can someone please lead me in the right direction?

Thank-you

2. May 26, 2013

Staff: Mentor

What's the pressure inside the submarine? (That's given.)

What's the pressure outside the submarine at the given depth? (Figure that out.)

What's the difference?