(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Recently I stumbled on an exercise in a physics book. My problem is, that I am confident there is a fault somewhere in the textbook, as my numbers don't add up with the ones in the "Answers" segment. The assignment:

A ship that sank off the coast of Aland during the Crimean war lies on a 40 m depth. Researchers want to investigate the the ships cargo from a small submarine. In the sub there is a "pressure equalization chamber" (airlock?) from which entrance to the water is possible from 1.00 m² hatch. a) calculate the hydrostatic pressure at this depth b) What is the pressure in the pressure chamber if the hatch is influenced by a 50.0 kN force? [tex]\rho[/tex]=1.03*10³ kg/m³ and p0=101 kPa

2. Relevant equations

The hydrostatic pressure p=[tex]\rho[/tex]gh

Total pressure at depth h p=p0 + [tex]\rho[/tex]gh

Pressure p=F/A

3. The attempt at a solution

a) Hydrostatic pressure at 40 m : 101*10³ + 1.03*10³*9,81*40 = 505 kPa

The answer provided by the textbook is 392 kPa

b) I assume that the force acting on the hatch is directed outwards (towards the sea) creating a a slight overpressure in the chamber to keep it from flooding as soon as the hatch is opened.

Then: p=F/A, 50000 N/ 1.00 m² = 50 kPa. The total pressure in the chamber should then be 50 kPa + 505 kPa resulting in a total pressure of 555 kPa in the chamber. The pressure in the chamber according to the textbook is 455 kPa.

I know the hydrostatic pressure at 40 m can in no way be less than 5 atm (505 kPa). Am I right or am I thinking wrong somewhere?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Problem with pressure

**Physics Forums | Science Articles, Homework Help, Discussion**