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!

A massless, frictionless pulley is suspended from a rigid rod

  1. Dec 31, 2003 #1
    A massless, frictionless pulley is suspended from a rigid rod. Two masses, m (50 kg) and M (60 kg), are suspended on either side of the pulley, respectively, by a light, inextendable cord. Determine the accelerations of the masses.

    I drew the force diagrams of both; there is an upward tension force and a downward gravity force in each. Mg - mg = (m + M)a. Now acceleration of block m is (M - m)g/(M + m) upward and block M's acceleration is the same but downward. So does m have a positive acceleration while M has a negative acceleration?

    Thanks.
     
  2. jcsd
  3. Dec 31, 2003 #2

    Integral

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Could be either, it depends upon how you define your coordinate system. Is postive up or down?
     
  4. Dec 31, 2003 #3
    I guess I define positive as going up on the coordinate sys. In the problem, m is pulled up while M goes down.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: A massless, frictionless pulley is suspended from a rigid rod
Loading...