MindShadowfax

Hi there everybody! I'm having trouble with this hw my teacher gave and i'd like you to help me as it's been quite difficult to find anything with Google. I'm supposed to get information about Green, Stokes and Gauss' theorems on: How could you relate them (at least in pairs) and some applications they have. I know that if my surface is plane and parallel to the coordinate axes Stokes = Greens. Another thing I've already got is that Green applied to a 1 is the curve-length , Stokes would give the surface and Gauss the volume, correct me if i'm wrong. So i'd basically be needing some real applications like in physics or any other field where it is used. Thank you very much, Merry xmas and happy new year to everyone!

Ok thanks, I had the exam today, I think I did great, I'll tell you next week

It doesn't really explain how did they move it just say that they move :S

So the friction is the cause.. I wasn't sure about that. And for example if I have 2 kids on a merry-go-round with certain angular velocity w0 and then they move to the center, they gain speed and also they have more energy, where did that energy come from? If you can explain that with forces, i'm just a beginner here

Hi everyone, this Thursday I have my Physics test and doing some exercises to practice I've noticed that in "rotational exercises" even though External Forces and Torques are = 0 you loose kinetic energy, for example when you have a rotating disc and then you put another one on the top of it, you loose angular speed because you gain mass but I am not sure of is how to explain the lost of energy. I'm guessing it is about the internal forces but I'd like someone who really knows to tell me the why, I'm not sure if I made myself clear with the question thank you guys!

Right now I'm too tired, I'll try to think about it tomorrow and check what other people said. Good luck with that one!

I'm not 100% about what I'm going to say as this is what i'm studying myself but take a look at this.. When you have the first int you posted then you would get IntInt(F(r(u,v) |N|) dS right? that's doing F=<xz;x;y> and looking at the surface with a parametric equation. Then you can use the Gauss Theorem Gauss int intF n dS = int int int div F dV And that is way easier. Sorry about the way i wrote the equations I don't know how to do it in a proper way. Anyway I'd do that Good luck