What do these variables mean?


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Bansi Amin 1D
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What do these variables mean?

Postby Bansi Amin 1D » Sun Jan 21, 2018 7:40 pm

I'm going through my notes and there was a line of reasoning of equations: w=FD; since F=PA then w=(PA)D=PΔV. I'm assuming that F represents force, D represents distance, and that A represents area, but I'm not too sure. The others I'm clear on. Can someone verify this for me? Thanks!

Mitch Mologne 1A
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Re: What do these variables mean?

Postby Mitch Mologne 1A » Sun Jan 21, 2018 7:56 pm

Those are correct!

Clement Ng
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Re: What do these variables mean?

Postby Clement Ng » Sun Jan 21, 2018 8:00 pm

Yep! P is pressure too.

Marina Georgies 1C
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Re: What do these variables mean?

Postby Marina Georgies 1C » Sun Jan 21, 2018 8:24 pm

Those are right! Also in the last step, AD turns into deltV (change in volume) because it is referring to area x distance (height). Page 263 of the textbook has diagrams that demonstrate this series of equations.

Jacob Cho 2L
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Re: What do these variables mean?

Postby Jacob Cho 2L » Sun Jan 21, 2018 10:45 pm

You are correct. F is force, A is area, D is distance. Interestingly Force can be defined as pressure over an area (F = P * A) and when that is put into the work equation (w = F * D), it becomes F = P * A * D. Then, A * D can simplify to ΔV because it represents the difference in volume before and after the work done (we can focus on the before and after volumes because work is a state function).


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