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Homework Help: Rotational Motion angular speed

  1. Oct 31, 2011 #1
    1. The problem statement, all variables and given/known data

    11. A wheel with an angular speed of 2.0 rad/s is rolling on a horizontal surface and starts down a ramp. It rolls down the ramp with a constant angular acceleration of 2.5 rad/s2. If it takes 8 s to reach the bottom of the ramp, what is the final angular speed of the wheel at the bottom?

    a. 20 rad

    *b. 22 rad/s

    c. 18 rad/s

    d. 25.5 rad/s

    2. Relevant equations


    3. The attempt at a solution

    I plugged into the equation initial velocity as 2.0rad acceleration as 2.5 and time as 8 and solved for final velocity which have me 20 rad/s the answer key says its 22
  2. jcsd
  3. Oct 31, 2011 #2
    The final angular speed consists of the initial angular speed plus the amount it accelerated on the ramp.

    Pertinent equation is: omega final = omega initial + alpha *time
  4. Oct 31, 2011 #3
    Ohh i did my math wrong sory
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