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Homework Help: Help with electric field problems

  1. Nov 10, 2004 #1
    I have two electric field problems that I need help solving:

    1. How strong an electric field is needed to support an electron against gravity on the surface of the earth?

    I know the charge of an electron is -1.60 x 10^-19C
    I think that you use the equation V=Ed, but I don't know what to do for the d dealing with earth.

    2. What is the acceleration of a proton in an elctric field of 1 x 10^4 N/C?

    This one I have no idea where to start. This problem is unlike any of the others that were given. It might deal with KE, but I'm not sure.

    Any help would be greatly appreciated!
    Last edited: Nov 10, 2004
  2. jcsd
  3. Nov 10, 2004 #2
    1. Gravity exerts some force on the electron. Also, an electric field will exert a force given by: F = qE. Can you see where this is going?

    2. What force must then act on the proton? Use Newton's second law to find the acceleration.
  4. Nov 10, 2004 #3
    Still not sure

    Using F=qE I know the q What is the F then? Is there a certain number for the gravity on the surface of the earth?

    I know that F= ma, but I'm not sure where to go from this any other help would be appreciated
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