Recent content by PeterPumpkin

What do we mean when we say "1 kg of bananas"? Homework Statement If I buy 1 kg bananas in a supermarket on the moon, will I get the same amount (mass) of bananas as if I bought them on the earth? Homework Equations w=mg g moon = 1/6 g earth The Attempt at a Solution It depends on...

I'm reading The Lightness of Being by Frank Wilczek and I'm trying to work out what credence I should give the idea of "The Grid". Several questions. Isn't his "Grid" just the same as the old fashioned idea of ether? If not, how does it differ from "ether"? How does this idea stand...

Wanted: video by Wilczek on "The Grid" Does anyone know of a video lecture on the WWW by Prof Wilczek describing his theory of the Grid? (Suitable for someone with a basic science knowledge.) Thanks.

Thanks. I was wondering could one calculate the screening from the virtual particle model? Seconding, I was wondering do all the virtual charges vanish within the gaussian suface? The virtual charges will be polarised and so, if you thinking of the charges that intersect the gaussian surface...

Does Gauss's Law apply to virtual particles? For example, when computing the field around a real proton, is the net charge in Gauss's Law the proton charge plus the contribution of all the virtual charges within the closed surface? (I'm thinking about the screening of charges by virtual...

Thanks. That would seem to imply there really are 5 fundamental forces in nature: Gravity, em, weak, strong force and the "colour force".

I'm reading The Lightness of Being by Frank Wilczek. The strong force falls off rapidly with distance. And yet when we attempt to separate two quarks the force increases enormously. I assumed the strong force acted between hadrons (= groups of quarks) and between quarks but this...

I'm reading The Lightness of Being by Frank Wilczek. In a footnote talking about screening of a (real) positive charge by virtual particles (p47), he says "Thus the force falls off faster than 1 over the distance squared, as you'd have without screening" (by virtual particles). How then...

Is it true that if you get a kink in an Ethernet cable (but without braking the wires), it will no longer work? Why is that? Is it related to the signal frequency? Or is it because of the material the cable is made out of ?

Thanks. I can see my mistake --- there's no way to define f(x) to satisfy the requirements.

Can h(x)=(cos x)^x be written as a composition of two functions f and g where f(x)=x^n and g(x)=cosx ? where h=fog REASON FOR ASKING: I am wondering this in connect with a differentiation I was having trouble with (but can now solve thanks to this forum). I mistakenly thought that I could...

Thanks. a) So, the chain rule eg putting u=cosx and y=u^x doesn't work in this case? Is that because the power is not a constant? Or is there some other reason? b) Yes, appreciate the cube root of -1 has complex roots. What puzzled me is that -1 didn't show as a valid root. I wondered why...

I wanted to differentiate (cos(x))^x Applying the chain rule I got -x(sinx)(cosx)^(x-1) But when I go to WolframAlpha, they show d/dx(cos^x(x)) = cos^x(x) (log(cos(x))-x tan(x)) Why the extra term? Why doesn't the simple chain rule apply? I have got strange results from WolframAlpha...

Homework Statement Why is the difference in electric potential between points A and B defined as the NEGATIVE of the work done in moving a test charge along the path from A to B and then dividing by the charge q? Why the negative sign? Just wondering. Homework Equations Delta V = -...

I'd assumed they were internal forces.