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: A small ball of mass M

  1. Mar 2, 2005 #1


    User Avatar
    Science Advisor
    Gold Member

    A small ball of mass M is attached t two identical springs of constant k, which are attached to the floor and the roof. The springs have unstretched lengh L/2. At what position will the ball remain at rest?

    The back of the book gives the answer.
    [tex]\frac{1}{2}L(1+\frac {Mg}{kL})[/tex]

    But the text doesn't do a good job explaining how to arrive at that answer. I've stared at it for 20 minutes. Any thoughts?
  2. jcsd
  3. Mar 2, 2005 #2

    Doc Al

    User Avatar

    Staff: Mentor

    When the ball is exactly in the middle (at L/2) what forces do the springs exert on it? And at a point a distance X beneath that middle point? What does X have to be so that the net spring force balances the ball's weight?
  4. Mar 2, 2005 #3


    User Avatar
    Science Advisor
    Homework Helper

    Okay draw the forces...Apply Newton's second law.And then use the fact that the body is equilibrium.

    The answer in the book gives the body-ceiling distance...

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook