J.C.MacSwell

I have a small (cross section 30" X 20") wind tunnel that is low speed (30 ft/s). For drag I use elastic from inside a bungy cord. I calibrated it and it was not linear (didn't follow Hooke's law) but it was reasonably consistent for crude measurements. For visualization I reach in with a wool tuft "tickler" on a coat hanger.I would like to use smoke at some point.

Good guess, a lot of the drag reduction in recent years has been accomplished by reducing lift.

Are they not the same thing?

Sorry, couldn't avoid it!

A 2 dimensional guy made this argument the other day If I were situated someplace, a rotation through 2 pi radians brings me looking where I was looking before. I think this basically proves space is two dimensional, since it would be true in the only plane which I know of. It was a little more forgivable for him, afterall, he's only 2 dimensional.

I think they originally figured that the photons interfered with each other and not with themselves in the two slit experiment etc. I think it was the Aspect experiments that proved that photons sent one at a time would (eventually) create an interference pattern.

Does light of equal frequency interfere as originally thought or is it the individual photons primarily "interfering with themselves"? Or do we know?

OK, let's get back to the point. Out in space if you push against me with F then I will push back with F and there will be no 2F resultant force on either one of us. If a bar is in between us and the bar does not move it works the same way. You push with F, I push back in the opposite direction with F and cancels it out for the bar . You are accelerated one way at F=ma and I am accelerated the opposite at F=ma.

Thank-you both and that link looks interesting.

Can comeone explain the difference between spin 1/2, spin 1 and spin 2 in such a way that the numbers make sense. I realize they mean quantum spin and relate to classic spin by analogy only but in what sense is spin 2 "twice" spin 1, or spin 1 "twice" spin 1/2. I realize also that spin 1 and 2 are in a different "family" than spin 1/2.

Is that your conclusion/you agree fully with it?

If equally hard means equal force... I said if we were equally powerful.

Maybe this will help: Assuming the force does not act through the centre of mass. All of the force will also go into rotation. The moment will depend on the magnitude of the force and the "lever" due to the alignment of the force wrt the centre of mass.

It takes more energy to maintain the force. If you and I were in outer space with bars and we were equally powerful and I pushed with all my might through the centre of mass and you pushed with all your might on the end as described on an equivalent bar then I would exert more force.