Pressure on a submarine window homework

mz.mary00

1. Homework Statement

A research submarine has a 40.0 -diameter window 8.30 thick. The manufacturer says the window can withstand forces up to 1.00×106 . What is the submarine's maximum safe depth?

2. Homework Equations
p=Po + pgh

3. The Attempt at a Solution
p = 1.01x 10^5 + ? X9.8 x 8.3

i dont know how to find that p since we were not given mass
please helppp i am so confused of what to do

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Anden

Hint: Pressure on the outside = Pressure on the inside, at max depth. Pressure on the outside depends on the density of the water, air pressure and depth. Pressure on the inside at max depth equals air pressure and strength of the window.

Note that it was a long time since I did this so I'm a little unsure

Doc Al

Mentor
2. Homework Equations
p=Po + pgh
That equation is:
Total Pressure = Atmospheric pressure + density*g*depth

What's the density of water? (You don't need the mass of anything.)

First figure out what pressure is needed to break the window. How does pressure relate to force?

p= F/A

mz.mary00

The pressure inside the submarine is maintained at 1.0 atm
do we ignore that fact

Last edited:

Anden

The pressure on the inside of the window is air pressure + something else, the "something else" has to do with the window.

Doc Al

Mentor
So use the given information to figure out the pressure that would break the window.
The pressure inside the submarine is maintained at 1.0 atm
do we ignore that fact
The question is ambiguous. "The manufacturer says the window can withstand forces up to 1.00×106 ." doesn't specify whether that is the net force or just the outside force.

I would pressume they meant the net force. (So ignore atmospheric pressure since it's canceled by the inside pressure.)

mz.mary00

in other words we have to find the outer pressure or is that the atmostpheric pressure, so what happens afterwards, i am not sure is that the atmostpheric pressure?

mz.mary00

then it becomes
Total pressure = 101.3+ (9.8 X d X 1000)

=101.3 + 9800d

and now my question is , how do i get my value for d?

Last edited:

Doc Al

Mentor
then it becomes
Total pressure = 101.3+ (9.8 X d X 1000)
What's the 101.3?

and now my question is , how do i get my value for d?
You'll solve for it. The pressure is not an unknown; you can figure it out from the information given about the window.

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