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Homework Help: Uniform cricular motion ( HELP ME PLASEEE)

  1. Oct 31, 2005 #1
    A horizontal force of 210n is exerted on a 2.0kg dicus as it rotates uniformly in a horizontal circle (at arms lenght) of radius .90m. calculater the speed of the dicus?

    here is what I have f =210N
    m = 2.0kg
    r = .90m

    f =ma a = f/m = 210N/2.0Kg a= 105
    x/t .90/105 is that right?
  2. jcsd
  3. Oct 31, 2005 #2

    Chi Meson

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    Right up until the last line.

    The acceleration is 105 m/s/s, but this is centripetal acceleration (toward the center, the kind of acceleration that changes the direction, not the speed of the velocity).

    look at the formula for centripetal acceleration, you will see speed there.
  4. Nov 1, 2005 #3
    Here's how i done it

    F = (mv^2)/r --> that's the formula that Chi meson referred to
    plugin your values

    F = 210, m = 2, r = 0.9

    and you should juggle it and get same answer as Chi
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