1. Not finding help here? Sign up for a free 30min 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!

Angular acceleration of a pulley

  1. Nov 8, 2009 #1
    1. The problem statement, all variables and given/known data
    A 2.70 kg bucket is attached to a disk-shaped pulley of radius 0.141 m and mass 0.792 kg. If the bucket is allowed to fall,
    A- What is linear acceleration?
    B- What is angular acceleration?
    C- How far does the bucket drop in 1.5 s?

    2. Relevant equations
    a=g/(1+ (I/mr^2))
    alpha=delta w/delta t

    3. The attempt at a solution
    i tried using both equations for a and b, but they both came up wrong
     
  2. jcsd
  3. Nov 8, 2009 #2

    rl.bhat

    User Avatar
    Homework Helper

    Show your calculations.
     
  4. Nov 8, 2009 #3
    9.8/(1+(2.7*.141^2)=4.9
    but this didnt work for either answer, and i dont know how to get time out of this, so im not real sure if you can use the second equation
     
  5. Nov 8, 2009 #4

    rl.bhat

    User Avatar
    Homework Helper

    (2.7*.141^2) This is only M*R^2. Bur in the relevant equation you need
    I/mr^2, where I is the moment of inertia of the pulley. Find this value.
     
  6. Nov 8, 2009 #5
    what about gravity, should i still use my original equation?
     
  7. Nov 8, 2009 #6

    rl.bhat

    User Avatar
    Homework Helper

    After substituting the value of I, the acceleration a is
    a = g/( 1 + M/2m)
     
  8. Nov 8, 2009 #7
    which m is which mass, is M the mass of the bucket, pulley or both? and is m the mass of the bucket, pulley or both?
     
  9. Nov 8, 2009 #8

    rl.bhat

    User Avatar
    Homework Helper

    M is the mass of the pulley, because I is the moment of inertia of the pulley.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Angular acceleration of a pulley
Loading...