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!

Frequency problem (static equilibrium)

  1. Jan 12, 2016 #1
    1. The problem statement, all variables and given/known data
    The lower end of a uniform beam is attached to a vertical wall by a frictionless pivot. The beam extends away from the wall and upward, making a 62° angle with the wall, and it is held in place by a horizontal wire attached from its upper end to the wall. The wire's length and mass are 4.98-m, 0.737-kg and the beam's weight is 349-N. The speed of sound is 344 m/s. When the wind blows, the wire vibrates in its 4th overtone

    2. Relevant equations
    T=Ialpha
    flambda = v

    3. The attempt at a solution
    First I wanted to find the tension force so I can find v...

    [itex] v = \sqrt {\frac{F_{t}}{\mu}} [/itex]
    Because the system is in static equilibrium I set [itex] \tau_{F_{g}} = \tau_{T} [/itex] .... [itex] \frac{m_{b}gL}{2} * sin(\theta) = TLcos(\theta) [/itex] .... [itex]T = \frac{m_{b}g}{2}tan(\theta) [/itex]

    Thus, [itex] v= \sqrt{\frac{\frac{m_{b}g}{2}tan(\theta)}{\frac{0.737}{4.98}}} = 9.456[/itex]
    [itex] \lambda_{5} = \frac{2L}{5} [/itex] ... solving for [itex] f* \frac{2L}{5} = 9.456 [/itex], I get the frequency is 4.747.... which isnt the correct answer.... can someone tell me where I'm going wrong? Thanks.
     
  2. jcsd
  3. Jan 12, 2016 #2

    ehild

    User Avatar
    Homework Helper
    Gold Member

    Check the value of v.
     
  4. Jan 12, 2016 #3
    bloody hell.
     
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: Frequency problem (static equilibrium)
Loading...