## Identifying Positive Potential Energy

$w=-P\Delta V$
and
$w=-\int_{V_{1}}^{V_{2}}PdV=-nRTln\frac{V_{2}}{V_{1}}$

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Jake Ney lecture 1 discussion 1F
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Joined: Fri Sep 25, 2015 3:00 am

### Identifying Positive Potential Energy

In problem 8.3 air in a bicycle pump is compressed by pushing in the handle. According to the solutions guide this work is positive with respect to air in the pump. This seems counter intuitive because work is being done on the system. Can somebody please explain how to identify when the work with respect to a system is positive or negative. Furthermore does positive work always entail that the energy of a system is also positive?

PriyaKohli3B
Posts: 31
Joined: Fri Sep 25, 2015 3:00 am

### Re: Identifying Positive Potential Energy

The work is being done by pushing the pump and internal energy is equal to heat plus work so if the work being done is positive the internal energy will also be positive! hope this helped!

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