Recent content by Unicorn.

Hello ! Homework Statement In an exercise we consider two surfaces given by f1=(x,y,f(x,y)) defined in a domain D And f2=f1 in D' And a line d with two parametrizations d1=(f(y,z),y,z) d2=(x,f(x,z),z) They ask to find the principal curvatures of S1 U S2 U d Homework EquationsThe Attempt at a...

In the example in the class the teacher explained that the little squares were local inertial reference frame (as elevators) and as the photon of a star were crossing them they fall in the direction of the sun. I'm sorry for the lack of informations, I'm trying to remember because my notes are...

dz is the width of the reference frame r is the distance between the reference frame and the center of sun gr gravitational interaction ge is the effective gravitational acceleration

"It" is to prove that d∅=go*cos3(α)/c² *dz It's the angle of deviation of a light beam in the gravitational field of the sun. What I'm trying to find is this expression d∅=go*cos3(α)/c² *dz from the drawing Thanks

In the course the teacher advised us to do it and just gave us the expression, so I'm trying to, my exam is Tuesday and I want to understand how we find dphi because it's from this equation, by integration that we find that phi=2*G*M/(c²*R) Thanks

Homework Statement Hello, I have a little problem with this figure, this is not an assignment or something else I just don't understand how we can find that d∅=gocos3(α)/c² *dz Homework Equations go=G*M/R² with R the sun's radius The Attempt at a Solution I wrote all what I can deduce...

Hello, We proved something during the course but I totally forgot how to do it.. Homework Statement Prove that Planck's Law E=h*u is deduced from the equation of Doppler effect u'=u*√((1-β)/(1+β)) Homework Equations Lorentz transformationThe Attempt at a Solution If we take a beam of light of...

Hello, Homework Statement A rope of mass M and length L is tend with tension T between two rings free to oscillate along a rod parallel to the y axis. Initially the rings are maintained at y=0 while we give to the rope a y(x,0)=dsin²(pix/L). Give the complete expression of motion of the rope in...

Hi, Homework Statement A rope of length L, linear density u is streched with tension T between a wall and a ring of negligible mass free to move vertically along a rod without friction. As the ring is maintained at y=0, we give to the rod a y(x,t=0) = sin(πx/L) form. We release the ring and...

Solved.

Hello, Homework Statement A charge q is at rest in frame O. In O' with velocity βc in x direction, at t'=0 the charge is at the origine O' and produce an electric field E' at position r'=(x',y',z') : E'=γ*q*(x',y',z')/(4πεo*γ²(x'²+y'²+z'²)3/2) If θ is the angle between r' and x, show...

Sorry, I didn't notice that i forgot it. "We neglect the extension of the wire and the change of the tension."

It says that we neglect the extension of the wire. Now, I don't know how to deal with the a/ question , is it a n function ?

I did c/ and I found U=2Th²/L I don't understand what you're asking for a/ ..?

I'm really confused. So the answer to (a) must be U=Tn²pi²A²/4L we use y(x,0) And for (b) it must be U=2Th²/L Then, for c/, they ask to show that the potential energy is the sum of potential energy of each mode by finding the same expression as b/ So I have to find U=2Th²/L, right ? The...