00:01
We have a sterling engine here.
00:04
A, b, and c, d are isotherms, and d .a and b .c are isochoric, which happens at constant volume.
00:15
We want to calculate a bunch of things.
00:17
We're told the volume at a and d is half a .5 cubic meters.
00:22
At b and c, it's .49 cubic meters.
00:26
T .a and tb are 500k, and t c and td are 2 ,500.
00:31
And we have 10 moles of a one of a monotomic ideal gas.
00:39
So part a was to draw the picture.
00:46
Part b, we're going to calculate the pressure at each point.
00:53
So in general, pressure is nrt over v.
00:57
We have all the numbers, so let's just substitute it in.
01:03
We use 8 .314 joules per mole degree for r, because our volumes are given in cubic meters.
01:16
Our pressures will be in pascal's.
01:49
There's pc and pd.
02:07
Okay.
02:08
Now we want to calculate the works.
02:12
So from a to b is an isotherm.
02:16
So the work is nrt times the log of the volume ratio, v final over v initial.
02:24
So that's negative 840 joules.
02:33
And then wcd, work cd, nrt, c, times the log of vd over bc, which comes out to be 4 .2 times 10 to the third joules.
03:00
And for bc and da, the work is zero because they're isochoric processes, so the volume is constant.
03:09
And they do zero work, or the winds on the pv plane or vertical.
03:22
Part d, you want to find the total work, which we just add all those up.
03:37
And we get 3 .36 times 10 of the third joules.
03:47
In part e, we want to find the heat.
03:53
So we know qab is minus 840 joules, because that's an isotherm, so the heat's equal to the work.
04:05
And on cd, it's also an isotherm, so that would be equal to that work.
04:20
On bc, so bc happens at constant volume.
04:27
So the heat at constant volume is just n -c -v -d delta -t.
04:37
And for us, c -sav -v is three -haves -r, because we have a monatomic ideal gas...