1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Magnet problem

  1. Apr 15, 2004 #1
    hey, I have a tough time cracking this one
    The other problem is:
    Imagine a glass tube with steel rings around it which have a conductancy rho and a half diameter of R. they are spaced with a distance H.
    inside the glass tube is a much smaller glass tube. Through it you drop a magnet with mass m and magnetic moment mu. the magnet will reach a final speed V quite soon. Explain with which factor the endspeed V will change if in five different experiments the five parameters(H,R,rho,M,mu) are doubled. You can neglect all form of friction, selfinduction and reciprocal induction.

    I have a partial answer. You have to express v in the five parameters and then it is easy. If the speed is constant all height energy over a height H will be transfered into electric energy, so MHg=Pt with P the electric power and t the time that it takes to fall down a length of H. that time t is V/H. P is I^2*R.
    So MHg=(V/H)*R*I^2. the problem is, how do you express I? mu=a*m^2 so I thought that the solution would be I=mu/(pi*R^2). (magnetic moment divided by area of one ring) But that can't be true because other rings have influence too, and now I just calculate the influence of one ring. Also, I don't take into account the distance between the rings. If you express V in this way H isn't in the formula, that can't be right. Help me please? thank you in advance.
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted