Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Turning effect of force (Moments)

  1. Oct 12, 2010 #1
    My previous post has been removed due to some reasons.
    I would like to ask another question: if a uniform metre ruler with weight of 1.2N, suspended at its mid-point from a spring balance. No other force is added to the ruler.
    The reading on the spring balance is 1.2N. Am I right?

    If the spring balance is move rightwards, which causes the ruler to rotate due to turning effect, will the reading on the spring balance be the same or will it vary because of the turning effect of the force.
     
  2. jcsd
  3. Oct 12, 2010 #2

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    it wasn't removed, it was combined by a mentor with your original post on the same topic.
    Yes, indeed.
    It will vary since it is no longer in equilibrium, since the center of mass of the meter stick is now accelerating vertically and horizontally (or tangentially and radially).
     
  4. Oct 12, 2010 #3
    thanks for your reply. ' It will vary since it is no longer in equilibrium'.. But I don't really get it. i thought the only force acting downwards is the weight of the meter stick. So if the reading on the spring balance varies, is it larger than 1.2N or smaller?
     
  5. Oct 12, 2010 #4

    PhanthomJay

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Don't forget that the stick is rotating and it is accelerating in both the tangential and radial directions. In addition to the weight force, there is a radial force in the meter stick from the centripetal acceleration. The scale reading varies from a minimum at the start to a maximum at the bottom of the circle.
     
  6. Oct 12, 2010 #5

    I think I have understood it with your clear explanation.
    I am really grateful for your help. :DD
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook