Hi, I'm taking a university extension program, so I can't talk with my professor. The Calc teacher at my high school doesn't understand the problem either.(adsbygoogle = window.adsbygoogle || []).push({});

The Problem:

Suppose that the gas in a circular cylinder of cross section area A is being compressed by a piston. If p is the pressure of the gas in psi, and V is the volume in cubic inches, the work done in compressing the gas from state (P1,V1) **(P sub 1, V sub 1)** to state (P2,V2) is given by the equation:

Work= [definite integral from (P2,V2) to (P1,V1)] p*dV

Find the work done in compressing the gas from V1=243 cubic inches to V2=32 cubic inches if P1=50 lb/cubic inch AND p and V obey the gas law pV^(1.4)=constant.

I cannot make heads or tails of this problem. I have never seen a coordinate pair used as a limit of integration.

I first thought that I should use the gas constant to make those limits into usable numbers, but P2 is not given.

I then thought that maybe I should use the gas constant (using P1 and V1) to find P2 (by setting P2(V2)^1.4 equal to the number given by plugging in P1 and V1). This creates a problem, making the upper and lower limit the same (109,350 is the exact number). This would defeat the purpose of integrating the equation, because the result would obviously be 0.

Any thoughts? Any help is greatly appreciated. My email is M_Daun@msn.com

**Physics Forums - The Fusion of Science and Community**

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!

# Need Timely Help with Unique Work by a Variable Force Problem

Loading...

Similar Threads for Need Timely Help | Date |
---|---|

B Need some help with understanding linear approximations | Feb 17, 2018 |

I Need help understanding this step in simplifying a limit equation | Apr 21, 2017 |

Find velocity and time, help needed | Jul 5, 2012 |

Time ball needs for a certain path/courve | Nov 16, 2005 |

Back again, need help one more time. | Sep 26, 2004 |

**Physics Forums - The Fusion of Science and Community**