# Calculate Pressure of Air in a Cylinder

1. Sep 3, 2009

### smeating

I am starting out with a cylinder that measures 4cm diameter and height is 12cm with the air being under no pressure. I then want to colapse the cylinder down to half of it's original height, pressurizing the cylinder. Can someone tell me what the pressure would be.

Thanks in advance for any help

cheers,

2. Sep 3, 2009

### KLoux

You may need to consider things like temperature, too - Google the Ideal Gas Law and read about the assumptions made for an Ideal Gas, then search for the Combined Gas Law, which is really probably what you're looking for.

-Kerry

3. Sep 3, 2009

### jasc15

This depends on the method of compression. If it is compressed rapidly, (i.e. adiabatically) both the temperature and pressure will increase. If the gas is allowed to return to the temperature it was before compression, the pressure will be different than in the previous example. There are different equations for each process (adiabatic and isothermal).