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!

Massless Pulley Problem

  1. Feb 27, 2013 #1
    1. The problem statement, all variables and given/known data

    A light rope is attached to a block with mass 4.00 kg that rests on a frictionless, horizontal surface. The horizontal rope passes over a frictionless, massless pulley, and a block with mass m is suspended from the other end. When the blocks are released, the tension in the rope is 10.0N.
    a.What is the acceleration of either block?
    c.Find the mass m of the hanging block.

    2. Relevant equations

    ƩF=ma

    3. The attempt at a solution

    My attempt at solving the problem is attached. Can someone tell me where I went wrong?
    (It got cut off at the bottom, it just says that my answer of 0.813kg is wrong, but I don't know why. THE CORRECT ANSWER IS: m=1.37kg
     
  2. jcsd
  3. Feb 27, 2013 #2
    Sorry, My attempt at the solution is now attached.
     

    Attached Files:

    • HELP.pdf
      HELP.pdf
      File size:
      151.1 KB
      Views:
      128
  4. Feb 27, 2013 #3

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    You've been inconsistent in your choice of directions. Which way is the mass m accelerating?
     
  5. Feb 27, 2013 #4
    Recheck your free body diagram. Where are the blocks accelerating? Specifically, on what axis as I am seeing two different axis here and that is not correct.

    EDIT: Sorry, didn't see haruspex's post when I responded, I did the same problem.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Massless Pulley Problem
  1. Non-massless pulley (Replies: 1)

  2. Massless Pulley Question (Replies: 12)

Loading...