# Homework Help: Total pressure at a depth in a fluid

1. Nov 8, 2013

### Molly1235

Hello,

I would just like some clarification on this...

When you calculate "total" pressure at a depth in a fluid do you have to add on the value for atmospheric pressure??

Thanks,
Molly :-)

2. Nov 8, 2013

### HallsofIvy

If you want to be very accurate, yes. However the atmospheric pressure adds so little to the pressure due to the fluid that most text book problems only deal with the fluid pressure. If you are asking about problems for a course, it would be best to ask your teacher.

3. Nov 8, 2013

### Molly1235

Ok, I was just confused because there was this one question from an old book that gave us the value of atmospheric pressure whereas none of the other questions have so I haven't included it but still got the answers right...thank you!!:)

4. Nov 8, 2013

### BruceW

the atmosphere has the same pressure as 10 meters depth of water, if I remember right. So if you are 20m underwater, then you will experience a pressure of 3 times normal.

edit: after seeing your reply, I guess the 'total pressure' was the total pressure with respect to atmospheric pressure. (i.e. not inlcuding the pressure of the atmosphere). I think this is fairly common.