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Car Acceleration homework questions

  1. Oct 13, 2008 #1
    1. The problem statement, all variables and given/known data

    Which of the following is true?
    a. None of these answers are correct.
    b. If a car is traveling eastward, its acceleration is eastward.
    c. A particle with constant acceleration can never stop and stay stopped.
    d. If a car is slowing down, its acceleration must be negative.

    2. Relevant equations
    a = v/t

    3. The attempt at a solution
    I'm not sure what the answer is. I'm thinking it's a, but I'm not really sure.
  2. jcsd
  3. Oct 13, 2008 #2


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    For a let's try to think of a simple analogy.
    a) If a man is jumping upward, his acceleration is upward.
    Can you see why this isn't true?

    b) A little ambiguous, but can you think of a way a particle can have a constant acceleration, and not be moving?

    c) Again, a little ambiguous... but I just picture everything here going in the positive x direction. Just think about how velocity and acceleration relate. acceleration = change in speed divided by change in time? If change in speed is negative, what is acceleration?
  4. Oct 13, 2008 #3
    I'd say it's "d". Slowing down is pretty much negative acceleration.

    b: The car might be going east, but it might be traveling at a constant velocity.
    c: Outside force to stop it.
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