## formula for work with integral

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

Anushi Patel 1J
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### formula for work with integral

Hi guys, can someone explain to me what Lavelle showed us in lecture with the work formula as a definite integral? Was that just to derive the work formula or will we be using that expression to solve questions?

Riya Shah 4H
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Joined: Wed May 02, 2018 3:00 am

### Re: formula for work with integral

I am assuming that we will have to use that in solving questions because he posted a document with rules of differentiation on his website.

makenzie2K
Posts: 31
Joined: Fri Sep 28, 2018 12:20 am

### Re: formula for work with integral

I believe he was trying to show us the relationship between the area under the curve of a work function and the first equation we derived for work. w=force x distance (which ultimately becomes -P x deltaV) since both equations give us an answer in this format I assume he was just showing us another way to calculate work.

monikac4k
Posts: 56
Joined: Fri Sep 28, 2018 12:25 am

### Re: formula for work with integral

I assume this formula would be used while the pressure and the volume are both changing at the same time. In this scenario, the pressure is no longer constant and the area underneath the pressure-volume curve wouldn't be a simple box. For complex functions modeling changes in pressure, calculus is required to find the area underneath the curve. This is when the integral would be useful. However, I don't think we will need to be solving integrals for this class.