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Homework Help: EASY PROBLEM - Force to break the string.

  1. Nov 20, 2006 #1
    A .208-kg toy whistle can be whirled in a horizontal circle of 1.00 m radius at a maximum of 3.00 rev/s b4 the string breaks. What is the force needed to break the string.

    I don't know how to start this problem but this is what i got.

    first i found frequency which is 1/3
    and then i got omega = 2pi 1/3

    i think this is all wrong cuz the answer is 73.9N

    someone please help!
     
  2. jcsd
  3. Nov 20, 2006 #2
    ook i read the problem wrong so it should be
    f=mac
    and then f=mv^2/r
    so iget 0.208 x v^2 / 1
    now how do i get v from the maximum revolution
     
  4. Nov 20, 2006 #3
    ok i got one revolution is 2pi (obviously)
    how do i implement that tothe problem to solve it.
     
  5. Nov 20, 2006 #4
    If 1 rotation is 2pi, how far does it travel in 1 second? This is the velocity.
     
  6. Nov 20, 2006 #5
    ok now i got everything im screwing up with this ti-89
    i did 6pi^2 which obviously registered as pi^2 x 6
    thanks
     
    Last edited: Nov 20, 2006
  7. Nov 20, 2006 #6
    ok now i got everything im screwing up with this ti-89
    i did 6pi^2 which obviously registered as pi^2 x 6
    thanks
     
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