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: Rotational dynamics, semicircular arc

  1. Jan 15, 2013 #1
    1. The problem statement, all variables and given/known data
    (see attachment)

    2. Relevant equations

    3. The attempt at a solution
    Do I need to take torque about C here?

    Any help is appreciated, Thanks!

    Attached Files:

  2. jcsd
  3. Jan 15, 2013 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper

    How else would you find the angular acceleration?
  4. Jan 15, 2013 #3
    I asked this because I am sure this would involve integrals and before doing the maths, I want to be sure if I am heading in the right direction. :smile:
  5. Jan 15, 2013 #4

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper

    If you can only think of one way to do a problem, it is worth a try: give it a go.
    Everything involves an integral if you don't already know the result.

    But it can help to have a think about the problem before starting:
    * If ##\beta=0##, what is the initial angular acceleration?
    * How does the total mass vary with ##\beta##?
    * How does the location of the center of mass vary with ##\beta##?
  6. Jan 15, 2013 #5
    I have solved the problem, I had trouble because I misinterpreted the problem. It looked to me like a semicircular arc but it isn't. Thanks! :smile:
  7. Jan 15, 2013 #6


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Yes, it's a poor drawing. The point where those angles meet doesn't look like it's supposed to be the centre of the arc.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook