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Homework Help: Determining force on an electron, possibly easy force problem(PLEASE HELP)

  1. Mar 23, 2009 #1
    1. The problem statement, all variables and given/known data
    An electron of mass 9.11 multiplied by 10^-31 kg has an initial speed of 4.00 multiplied by 10^5 m/s. It travels in a straight line, and its speed increases to 7.00 multiplied by 10^5 m/s in a distance of 5.00 cm.

    (a) Assuming its acceleration is constant, determine the force exerted on the electron.

    (b) What is the ratio of this force to the weight of the electron, which we neglected?

    2. Relevant equations
    i think you need some kinematics equations not sure though

    3. The attempt at a solution
    havent figured out where to start
    Last edited: Mar 23, 2009
  2. jcsd
  3. Mar 23, 2009 #2
    Hi unoriginal, welcome to PF.

    Why not? Let's start with part a) as its relatively straight forward. A good first step is to identify what data is given and what conditions are imposed.

    For example, you are given the "mass". What other data are you given? What is the condition as described in part a).
  4. Mar 23, 2009 #3
    to be honest its the whole scientific notation thing thats throwing me off lol
  5. Mar 23, 2009 #4
    Okay, then make sure all of your units are in basic units; that is, kilograms, meters, seconds. Then you should be fine.
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