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Electrons moving and entering regions. Mesuring vertical position and exit angle.HELP

  1. Nov 8, 2011 #1
    1. The problem statement, all variables and given/known data
    Electrons moving initially at 2.4 X 106 m / s in a horizontal direction. They enter a region between two plates of 2 cm in length and are subjected to an acceleration of 4x 1014 m/s2, vertical and pointing upwards. Determine:
    a) the vertical position of the electrons as they exit the region between the plates
    b) the exit angle


    2. Relevant equations
    Honestly, I dont even know where to start with this, I have no idea what it looks like! Can someone explain it to me, at least, what Its asking, in english?


    3. The attempt at a solution
    Can't even try, i dont get it.
     
  2. jcsd
  3. Nov 8, 2011 #2

    Redbelly98

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    Re: Electrons moving and entering regions. Mesuring vertical position and exit angle.

    This is a projectile motion problem. But, instead of the acceleration being g=9.8 m/s2, it is 4x1014 m/s2, downward.
    Also, each electron travels 2 cm for the horizontal displacement, and we are given the initial velocity.

    Hope that helps.
     
  4. Nov 8, 2011 #3
    Re: Electrons moving and entering regions. Mesuring vertical position and exit angle.

    Yes it does help, very much so! Thank you! I'll try that :)
     
  5. Nov 9, 2011 #4
    Re: Electrons moving and entering regions. Mesuring vertical position and exit angle.

    I still don't understand the 2 cm long plates buisiness though... cant seenm to picture what it looks like?
     
  6. Nov 9, 2011 #5

    Redbelly98

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    Re: Electrons moving and entering regions. Mesuring vertical position and exit angle.

    It would look something like this:
    [PLAIN]http://teachers.sduhsd.k12.ca.us/gstimson/charonplatesPphys5.gif[/INDENT][/INDENT] [Broken]
    Each electron is starts out moving horizontally and passes in between the two square plates, say moving from left to right. When an electron is in between the two plates, it has an acceleration 4x1014 m/s2 downward. When it is outside of the plate area it has an accleration of g = 9.8 m/s2, which can be ignored in comparison to the 4x1014 m/s2 acceleration.

    In this problem, the square plates have a side length of 2 cm. Therefore the electron only experiences the 4x1014 m/s2 acceleration over a horizontal distance of 2 cm, i.e. while it is in the area between the two plates.​
     
    Last edited by a moderator: May 5, 2017
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