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!

Rotating mass connected to elastic spring (help needed)

  1. May 8, 2012 #1
    1. The problem statement, all variables and given/known data

    A mass m connected using elastic spring to the roof.
    the mass is rotating horizontaly.

    Physics1.jpg

    mass m= 0.6kg
    rate or spring constant (k) = 40 N*m-1
    frequency= 1/2 sec-1
    spring's equilibrium length is 0.8m


    The question is:
    what is the length (L) of the spring while the mass rotating?
    (earths gravity of course)


    2. Relevant equations

    F(spring)= -kΔx
    F(gravity)=mg
    Fr= mω2r


    3. The attempt at a solution

    What I did is:
    On y: Tsinθ=mω2r
    now r=L*sinθ
    And T = kΔx = k(L-0.8)
    ω = 2*pi*f = pi
    → k(L-0.8)*sinθ=mω2*L*sinθ

    →→ L=0.939


    Now the problem is, that I believe that my colculation proves that
    gravity have no effect on the length of the spring, and I can hardly
    believe that, In fact Im almost sure that Im wrong.

    Hope you can help me find my mistake!
    thanks!
     
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted



Similar Discussions: Rotating mass connected to elastic spring (help needed)
Loading...