1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    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!

Question about kinematic equation

  1. Dec 1, 2011 #1
    Assuming initial angular velocity is 0 I want to solve for final position theta

    Ang Acceleration = Δw/Δt = w/t

    w = Δ(theta)/Δt = theta/t

    ang acc = theta/t^2

    theta = (ang acc)(t^2)

    but how come the kinematic equation is...theta = (ang acc)t^2/2

    Where did my 2 go?
  2. jcsd
  3. Dec 1, 2011 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    this formula gives the average angular velocity. You are looking for the instantaneous final angular velocity, which is twice the average.
    The displacement theta is {(wo+wf)/2} (t)
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook