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 change in KE of the proton?

  1. May 20, 2003 #1

    Dx

    User Avatar

    A proton moves .1 m along the direction of an electric field of magnitude 3 V/m. What is the change in KE of the proton?

    Is this the corrrect formula? KE = Q_pV_accel

    Through substition i came up with an swer of 3.2x10^-20J but i dont think its correct?
    Can you help me solve for this please?

    Thanks!

    Dx :wink:
     
    Last edited by a moderator: Feb 5, 2013
  2. jcsd
  3. May 20, 2003 #2

    Tom Mattson

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Re: Capacitance

    Can you explain what those terms mean?
     
  4. May 20, 2003 #3

    Dx

    User Avatar

    Re: Re: Capacitance

    Sure Tom,

    KE=Kinetic Energy
    Q_p=Charge of potential
    V_accel=velocity of acceleration

    Its not the correct formula huh?
     
  5. May 20, 2003 #4

    Tom Mattson

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Dx,

    There is no such thing as a "charge of potential" or "velocity of acceleration". I think you have those concepts muddled up. The kinetic energy K that a charge q acquires while being accelerated through an potential difference* V=Ed is:

    K=qV=qE/d

    *I can use V=Ed because that is valid for parallel plate capacitors.
     
  6. May 21, 2003 #5
    proton mass = 1.6e-27 kg
    proton charge = 1.6e-19 C
    distance = 0.1m
    E = 3 V/m
    mv2/2 = energy (non-relativistic)
    KE=qE/d...
    just pick up the calculator.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook