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: Restoring Force- any suggestions?

  1. Apr 23, 2008 #1
    1. The problem statement, all variables and given/known data
    An object of mass m is connected between two stretched rubber bands of length L. The object rests on a frictionless surface. At equilibrium, the tension in each rubber band is T. Find an expression for the freq. of the oscillations perpendicular to the rubber bands. Assume the amplitude is sufficiently small that the magnitude of the tension remains essentially unchanged.

    2. Relevant equations

    3. The attempt at a solution

    Here's what I tried, but I have no idea if it's right.

    I drew a picture, and found that as it oscillates, the tension in each rubber band in the direction perpendicular to the rubber bands is Tsintheta. Using the small angle approximation, I come up with T(d/L) Where d is the distance perpendicular from the original position of the mass. So the total restoring force is 2T(d/L)

    and then I set that equal to the restoring force with the spring constant

    2T(d/L)=kd and came up with an expression for k and then substuted that into the frequency equation. Any suggestions?
  2. jcsd
  3. Apr 23, 2008 #2
    your method is completely correct.
    Because its simple harmonic motion (i.e. no damping or forcing) all you need to know is the mass (given) and the force - which you found, and looks right.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook