Recent content by miew

  1. M

    Cylindrical electromagnetic cavity.

    Homework Statement A cylindrical electromagnetic cavity 4.8cm in diameter and 7.3 cm long is oscillating. a) Assume that, for points on the axis of the cavity Em=13kV/m. The frequency of oscillation is 2.4 GHz. For such axial points, what is the maximun rate (dE/dt)m, at which E...
  2. M

    Prove that a great circle is a geodesic

    Homework Statement L = R \int \sqrt{1+ sin^2 \theta \phi ' ^ 2} d\theta from theta 1 to theta 2 Using this result, prove that the geodesic (shortest path) between two given points on a sphere is a great circle. [Hint: The integrand f(\phi,\phi',\theta) in the result is independent of...
  3. M

    Calculating the Magnetic Field in Free Space

    Okay, I am going to try that ! Thanks :)
  4. M

    Calculating the Magnetic Field in Free Space

    Differentiate with respect to what ? :/
  5. M

    Calculating the Magnetic Field in Free Space

    Okay, I start with a general B. So then, ∂yBz-∂zBy= Eocos(A) (where A is everything after cos) ∂zBx-∂xBz= Eocos(A) ∂xBy=∂yBx=0 Is that right ? if it is, how do I solve it ?
  6. M

    Calculating the Magnetic Field in Free Space

    Yes, they are unit vector. And the x inside the sin it is supposed to be a z, sorry :/ So aren't there two directions in which B can be perpendicular? x+z and y+z ?
  7. M

    Calculating the Magnetic Field in Free Space

    Homework Statement If the electric field in free space is E=Eo(x^+y^)sin(2pi/lamda)(z+ct), with Eo=2 statvolts/cm the magnetic field, not including any static magnetic field, must be what? 2. Relevant equation ∇ x B= 1/c ∂E/∂t The Attempt at a Solution First I calculated ∂E/∂t=...
  8. M

    Solving Del Cross Question: Why is del x dB/dt = mu dJ/dt?

    Homework Statement I have to do an E&M problem, I think I got it, but I made a few steps that I don't really understand. The first one is: If delxB= muJ Does del x dB/dt = mu dJ/dt ?? If so, why ? I tried using latex, but it didn't work...sorry :( Homework Equations...
  9. M

    Solve the Juggler Problem: Find Vo for Rod to Make Integer Number of Rotations

    Oh you are right !:smile: THank you so much for your help, you were really helpful :smile:
  10. M

    Solve the Juggler Problem: Find Vo for Rod to Make Integer Number of Rotations

    (I can't find your omegas and pi...:( ) Okay, so this is what I got. t=2npi/\omega Vf=v0-gt and since Vf=0, v0=gt but it goes up and down, so the total time is t=2vo/g. And then, v0=gnpi/\omega Is that right ? :)
  11. M

    Solve the Juggler Problem: Find Vo for Rod to Make Integer Number of Rotations

    (didn't I use omega :/ ? ) So the time to make one rotation is t= 2 \pi / \omega0 right ? And in that time it goes up a distance x= Vot - \frac{1}{2}gt where t is the one above ? Am I in the right track ? :)
  12. M

    Solve the Juggler Problem: Find Vo for Rod to Make Integer Number of Rotations

    So, for the linear motion: V=V0-gt And for the rotational motion: \omega= \omega 0+\alphat Cupid.callin what do you mean by lest rod goes up by some distance l?
  13. M

    Solve the Juggler Problem: Find Vo for Rod to Make Integer Number of Rotations

    b]1. Homework Statement [/b] A juggler is juggling a uniform rod one end of which is coated in tar and burning. He is holding the rod by the opposite end and throws it up so that, at the moment of release, it is horizontal, its Center of Mass is traveling vertically up at speed vo and it is...
  14. M

    Partial derivatives and change of variables

    Oh okay ! thank you so much ! you were really helpful :)
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