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: Circular Rotation Question

  1. Oct 11, 2004 #1
    A disk of radius .12 m starts accelerating from rest at 8 rad/s^2 At t = 5s

    A)What is the Angular Velocity
    This one is easy.. Av = 8rad/s^2*5 = 40 rad/s
    And makes sense.

    B)What is the tangential Accel?The book gave answer of .96 m/s^s Therefor, i assumed that the equation is At = w*r w=omega which is 8 rad/s^2 * .12m = .96 m/s^2

    However, later I found an equation for At given as At=dv/dt
    What gives? Which equation is correct for Tangential Accel? If they are both correct then how would I use At=dv/dt?

  2. jcsd
  3. Oct 11, 2004 #2
    Both are correct,

    Remember dv/dt is nothing but d(r*Av)/dt and since r is constant r*d(Av)/dt
    which is nothing but r*w... which was the first equation you used...
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook