1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Angular motion

  1. Jan 6, 2005 #1
    A coin with a diameter of 2.30 cm is dropped onto a horizontal surface. The coin starts out with an initial angular speed of 18.4 rad/s and rolls in a straight line without slipping. If the rotation slows with an angular acceleration of magnitude 2.17 rad/s2, how far does the coin roll before coming to rest?

    Can anyone help- I'm trying to study for a physics final and I'm getting nowhere!!! Thanks.
  2. jcsd
  3. Jan 6, 2005 #2
    Unless I'm missing something here, you can use this formula:

    vf2 = vi2 + 2aΔx

    Dividing both sides by R2, the coin's radius squared, we get:

    ωf2 = ωi2 + 2αΔθ

    Where α is the coin's angular acceleration, which is negative in this case. From here you can find Δθ and multiplying by R you can find the total distance travelled by the coin.
    Last edited: Jan 6, 2005
  4. Jan 6, 2005 #3
    Great.....thanks :biggrin:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook