Recent content by Jerry Friedman

Thank you! That seems to be the answer, as both Giancoli and Katz define the coefficients in terms of ##\Delta##'s, not derivatives. I should have noticed.

Thanks. Why would you be surprised? Fishbane (correct spelling, sorry), Gasiorowicz, and Thornton: "We can show that β = 3α by considering a cube of volume V = L3." Then they differentiate. Young and Freedman differentiate first, then say, "This is consistent with the infinitesimal form of...

I have two questions on fine points of thermal physics. 1. Is an isotropic solid's volume-expansion coefficient beta exactly equal to 3 times its linear-expansion coefficient alpha, or is it only approximately equal? Some textbooks (Fischbane, Walker, Young) say the relation is exact, while...

Thank you, Orodruin and Mentz114. I may be back with another question.

Is there something in General Relativity whose value is 9.8 m/s2 at the surface of the Earth?

robphy: That thread is the reason I called this one "Another person trying..." http://www.numericana.com/fame/ gives the mathpages' Kevin S. Brown's address as Kent, WA, with no academic affiliation. "White Pages" sites give a mailing address for a Kevin S. Brown in Kent. So unless someone...

I'll add that practice includes reading as well as writing. In addition, corrections help. I learned a lot of Spanish by participating in alt.usage.spanish (on Usenet), where we discussed various things and people corrected my errors. Alt.usage.english might work for you. There are probably...

I suppose there's still no way to get in touch with the author of the interesting page http://www.mathpages.com/home/kmath633/kmath633.htm ? I want to inform him that the page contains the phrase "Large Hardon Collider". Sic. Actually, I'm mostly hoping he'll see this.

Santa Fe. N. M. (I do not speak for Santa Fe Community College, my employer.)

Sorry to take so long. The students aren't winding transformers, but it's quite possible they've made excessive currents. I think looking into exactly what the the surviving AC sources are doing and why the broken ones are broken is a great idea, but I haven't been able to get in touch with...

Thanks, I don't know why I didn't think of that.

Find the coordinates of point A and use the distance formula to get AB. There are pleasant cancellations.

6?

They don't work with 110 V. They measure the input and output of "dissectible" transformers and hope that V2 / N2 = V1 / N1. I'm just looking for a power source.

These are replacing things like an Educational Equipment AC/DC power supply, or things that look like thishttps://www.amazon.com/dp/B0002DVEZA/?tag=pfamazon01-20, but the results in this lab haven't been good, and I'm starting to wonder whether the problem was with the power supplies. I think a...