<div dir="ltr"><div>Thanks everybody. Anybody else? Remember, please no peeking. Your efforts have already helped me identify an ambiguity in how I stated the problem. Here is an edited version. See if that clarification changes any answers.</div><div>Remember, no peeking before you kick in your answers. No herding allowed. </div><div><br></div><div>
<span style="font-family:comic sans ms,sans-serif">Side by side, butt-to-butt, two cylinders of air, of equal
volume and equal temperature, but different histories. They are separated by a frictionless
sliding divider which is now pegged.<span> Before compression or
heating, both started with air at 10 degrees C, and after compression or
heating, both arrive at 20 degrees C. </span>The
left one has arrived at its present temperature and volume by being
compressed,
the right-hand one by having its volume set to the same value as the
left, BEFORE BEING FILLED WITH AIR AT 20 DEGREES C, and ONLY then having contents heated. All compartments insulated, all
manipulations quasi-static.
Now, remove the peg, allowing the partition between the two parts to
slide, one way
or the other.<span> </span>Which way would it slide and why. What would
your explanation be? Please don't read others' answers until you have
submitted your own. This is enormously helpful to me. </span></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, May 27, 2025 at 10:19 PM Pieter Steenekamp <<a href="mailto:pieters@randcontrols.co.za" target="_blank">pieters@randcontrols.co.za</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Assuming the pressures were equal at the start, it will slide from the left (having been compressed) to the right.<br>From the ideal gas law PV = nRT, both have equal nRT;s so the one with smaller V must have higher P and it would then push to the right.</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, 28 May 2025 at 04:59, Nicholas Thompson <<a href="mailto:thompnickson2@gmail.com" target="_blank">thompnickson2@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>
Side by side, butt-to-butt, two cylinders of air, of equal
volume and equal temperature, but different histories. They are separated by a frictionless
sliding divider which is now pegged.<span> Before compression or
heating, both started with air at 10 degrees C, and after compression or
heating, both arrive at 20 degrees C. </span>The
left one has arrived at its present temperature and volume by being compressed,
the right-hand one by having its volume set to the same value as the left and then having contents heated. All compartments insulated, all manipulations quasi-static.
Now, remove the peg, allowing the partition between the two parts to
slide, one way
or the other.<span> </span>Which way would it slide and why. What would your explanation be? Please don't read others' answers until you have submitted your own.</div><div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div>Nicholas S. Thompson</div><div>Emeritus Professor of Psychology and Ethology</div><div>Clark University</div><div><a href="mailto:nthompson@clarku.edu" target="_blank">nthompson@clarku.edu</a></div><a href="https://wordpress.clarku.edu/nthompson" target="_blank">https://wordpress.clarku.edu/nthompson</a></div></div></div></div>
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</blockquote></div><div><br clear="all"></div><br><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div>Nicholas S. Thompson</div><div>Emeritus Professor of Psychology and Ethology</div><div>Clark University</div><div><a href="mailto:nthompson@clarku.edu" target="_blank">nthompson@clarku.edu</a></div><a href="https://wordpress.clarku.edu/nthompson" target="_blank">https://wordpress.clarku.edu/nthompson</a></div></div>