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Homework Help: Quick acceleration word problem

  1. Aug 9, 2008 #1
    1. The problem statement, all variables and given/known data
    An electron has an initial speed of 3.0 x10^5 m/s. It undergoes an acceleration of 8.0 x 10^14 m/s/s. (a) How long will it take to reach a speed of 5.4 x 10^5 m/s? (b) How far will it have traveled in this time?

    2. Relevant equations

    Rate x Time= Distance

    3. The attempt at a solution

    A. R x T= D

    (8.0 x 10^14 m/s/s)(T)=(5.4 x 10^5 m/s)-(3.0 x10^5 m/s)

    T= 3x10^18 seconds

    B. How do you find the distance traveled? This is stumping me for some reason.

  2. jcsd
  3. Aug 9, 2008 #2


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    Assuming the magnitude of acceleration is correct, that's a huge acceleration.

    The T should be quite small.

    What is the relationship between the change in velocity, acceleration and time?
  4. Aug 9, 2008 #3


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    Staff Emeritus
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    Homework Helper

    Joe has the correct relation, even if the terminology is a bit odd ("Distance" is really change in velocity, "Rate" is acceleration). He just needs to carefully redo the arithmetic given by that relation.

    Part B: your textbook has 3 or 4 equations for motion with a constant acceleration. Look over them, and choose one which can be solved for distance using the given information.
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