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: What is the magnitude of v?

  1. Mar 7, 2009 #1
    A circuit is pulled with a 16-N force toward the right to maintain a constant speed v. At the instant shown, the loop is partially in and partially out of a uniform magnetic field that is directed into the paper. As the circuit moves, a 6.0-A current flows through a 4.0- resistor.

    What is the magnitude of v?
    (a) 1.5 m/s (c) 6.4 m/s (e) 12 m/s
    (b) 3.0 m/s (d) 9.0 m/s

    the answer is (d) but i don't understand why
     
  2. jcsd
  3. Mar 7, 2009 #2
    V.F=Effect=ampere*volt*=resistance*ampere^2

    Put in numbers
    v*16N=4ohm*36A^2
    v=9m/s
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook