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!

Pulley Problem With Tension Direction

  1. Mar 20, 2013 #1
    In the attached picture, one sees a pulley with a mass which is holding two different weights. In chegg, the tension due to a weight is represented as a downward direction. Then, when the tension is seen in relation to the pulley, the direction switches for both weights. WHY IS THIS?!


  2. jcsd
  3. Mar 20, 2013 #2
    What problem is it? Can you tell me what it is or what problem from chegg you are trying to understand?
  4. Mar 20, 2013 #3
    The two blocks in the figure are connected by a massless rope that passes over a pulley. The pulley is 12cm in diameter and has a mass of 2kg. As the pulley turns, friction at the axle exerts a torque of magnitude 0.5Nm. If the blocks are released from rest, how long does it take the 4 kg block to reach the floor?
  5. Mar 20, 2013 #4


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    It's standard action and reaction. A weight pulls down on a string with an equal and opposite force to that with which the string pulls up on the weight. Similarly between string and pulley, and between each little section of string and its neighbours.
  6. Mar 20, 2013 #5


    User Avatar
    Science Advisor
    Homework Helper

    Hi Cameron! :smile:
    Tension is a force.

    The tensions at the two ends of a rope are opposite (and equal in magnitude if the rope is massless). :wink:
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: Pulley Problem With Tension Direction