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Homework Help: Question about Circular Motion

  1. May 18, 2014 #1
    1. The problem statement, all variables and given/known data

    Acceleration is a vector representing the rate of change of velocity. An object moving in a circle at constant speed:

    A. accelerates without changing its velocity
    B. Has constant acceleration
    C. Changes speed but not velocity
    D. Changes velocity but not speed

    2. Relevant equations


    3. The attempt at a solution

    The answer given in my book is D, which makes sense, but I also don't see how B is wrong. If the object's speed is constant, and radial acceleration is based off the magnitude of velocity (hence changing direction of velocity doesn't affect it), then shouldn't the acceleration also be constant?
  2. jcsd
  3. May 18, 2014 #2


    User Avatar

    Remember that acceleration is a vector; it has a direction.
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