an air rifle shoots a lead pellet by allowing high pressure gas to expand.(adsbygoogle = window.adsbygoogle || []).push({});

This happens quickly so it is an adiabatic process. initially 12 cubic centimeters of air are admitted to the barrel. It behaves as an ideal gas, [tex]\gamma = 1.40[/tex]. The air expands behind a 1.1 g pellet and pushes on it as a piston with cross sectional area 0.03 cm^2. the pellet emerges from the barrel with speed 120 m/s.

I am to use the work gone by the gas:

[tex] W = (\frac{1}{\gamma - 1})(PiVi - PfVf)[/tex]

to calculate the initial pressure required.

I do not know though how to find the final volume and final pressure...

I thought to use [tex]PfVf^\gamma = PiVi^\gamma[/tex] but this does not seem to change anything for me i still need to know Vf...

any help on this....thanks

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# Homework Help: Pressure and gas expansion

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