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Homework Help: Uniform Circular Motion of a tire

  1. Jan 24, 2010 #1
    1. The problem statement, all variables and given/known data

    A point on the outer rim of a tire on a moving
    vehicle exhibits uniform circular motion with
    a frequency of 28 Hz. The diameter of the tire
    is 40 cm.
    How fast is the car moving?
    Answer in units of km/hr.

    2. Relevant equations

    V=2 pi r f

    3. The attempt at a solution

    The first thing I did was finding the frequency in terms of hrs, and I got 100800 revelotions per hr. Then I found converted the radius to km so I got .0002 km. Then I found the velocity which is, 2 pi r f = 126.669 km/hr. My answer is wrong, I don't know what it is that I did wrong so if you can please help. Thank you
  2. jcsd
  3. Jan 24, 2010 #2
    I'm getting the same answer. If I had to guess, your book/teacher probably miscalculated or had a typo.
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