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: Magnetic field on a slope

  1. Oct 27, 2005 #1
    :uhh: The two conducting rails in the drawing are tilted upwards so they make an angle of 30.0° with respect to the ground. The vertical magnetic field has a magnitude of 0.048 T. The 0.22 kg aluminum rod (length = 1.6 m) slides without friction down the rails at a constant velocity. How much current flows through the bar? p21-35.gif

    ok so i'm really completely lost here, but let me give you guys what i'm thinking, see if you could lead me in the right direction

    I'm expecting that you don't use that 30 degrees as part of F= ILB sin(theta), but rather you use it to find force with F=ma right? if thats the case, how would you find the acceleration? would it just be 9.8 for gravity, or would it be something else because you're not going straight down...... but then i have a problem with velocity being constant, which means there would be no acceleration.... but there has to be gravity.......

    (i'm sorry if i seem all over the place :confused: just confused)

    so here's what i've done and it didn't work


    F= .22 * 9.8sin30
    F= 1.078
    F= I L B sin(theta)
    1.078= I 1.6*.048 sin 90
    I =14.036

    thats not the right answer, but to me that seems the only logical way to go about answering this problem.... any info would help thank you!
  2. jcsd
  3. Oct 27, 2005 #2
    Nevermind i figured it out, its sin(60), not sine of 30 or 90.... you can kill this thread if you wish!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook