4/12.65 – Physics Help Please! Work done on a gas *Hard Problem*?

Question

Please refer to image: http://session.masteringphysics.com/problemAsset/1036226/3/jfk.Figure.P12.65.jpg

99J of work are done on the gas in the process shown in the figure.

What is Vf in cm^3?

Answer 1

Now, the work is area under the line - again the p*dV integral - so it's: 99=2*x*200, so x=0.2475liters, so 247.5cmcubed

Answer 2

Work done on gas  =  pressure  x  change in volume

       99J     =      200,000  x  change in volume

Change in volume  =  99 / 200,000    =    0.000495 m^3

From graph, this is for a cjange of 2 Vf

       So     2 Vf    =    0.000495 m^3

                     Vf   =    0.0002475 m^3

                                 or  247.5 cm^3