1. Not finding help here? Sign up for a free 30min 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!

Electric field / charged plates question.

  1. Sep 21, 2008 #1
    I have this as an online assignment and think I have the wrong answer, but the site is telling me the result is wrong and takes a percentage off my grade each time i send a wrong submission.

    I am just posting an image link because that way you guys can see the picture:

    http://img142.imageshack.us/my.php?image=screenhunter003xp5qz5.png

    Here is what I have so far:


    t = length of plates / horizontal velocity

    = 2.20 * 10-2 m / 18.0 m/s = 1.22 * 10-3 s

    In the same time, the drop must deflect by 'd' distance along vertical direction. By second equation of motion

    d = uy * t + (1/2) * ay * t2

    uy = initial velocity along vertical direction = 0

    ay = acceleration along vertical axis.

    => 0.300 * 10-3 = 0 * t + 0.5 * ay * (1.22 * 10-3)2

    ay = 3.0 * 10-4 / 1.49 * 10-6 = 2.01 * 102 m/s2

    __________________________________________________________

    F = q * E

    by Newton's second law F = m * a

    => m * ay = q * E

    q = m * ay / E = 1.0 * 10-11 * 2.01 * 102 / 7.90 * 104

    q = 2.54 * 10-14 C

    But this is wrong and the site won't give me a feedback. If anyone can help me out, I would be very thankful. : )
     
  2. jcsd
  3. Sep 21, 2008 #2

    Defennder

    User Avatar
    Homework Helper

    Check your value for ay again.
     
  4. Sep 21, 2008 #3
    I did, it is 2.01 *10^2. Sorry, when I pasted, all the carrot signs disappeared.

    Is there anything wrong with any of the steps?

    Thanks.
     
  5. Sep 21, 2008 #4
    anyone?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Electric field / charged plates question.
Loading...