1. Oct 18, 2009

Neil6790

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

When air expands adiabatically (without gaining or losing heat), its pressure P and volume V are related by the equation PV^(1.4)=C where C is a constant. Suppose that at a certain instant the volume is 450 cubic centimeters and the pressure is 81 kPa and is decreasing at a rate of 10 kPa/minute. At what rate in cubic centimeters per minute is the volume increasing at this instant?

2. Relevant equations

I have no idea what any relevant equations would be.

3. The attempt at a solution

I don't know really where to start but I figured the kPa would be 71 and then 61 and so on... Maybe I take the derivative of the entire thing but that's an option

2. Oct 18, 2009

tnutty

You have :

PV^(1.4)=C

Try differentiate it. If you do you will see it become a algebra problem where you will
be solving for dv.

3. Oct 19, 2009

blake knight

I agree with tnutty, try differentiating it implicitly with respect to t(time).