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Circular motion please help

  1. Sep 29, 2006 #1
    All right i have a big test on monday in physics and the only thing my proffesor gave to me to study was this and i really dont know where to begin

    A boy spins a 5kg mass on a string of length 1.3 meters. He initially spins it with a constant linear velocity of 4m/s. At time=0 , it is at 3pi/4 radians, and he begins to give it a constant angular acceleration of a = .8rad/s/s. The maximum tension the string can withstand without breaking is 230N.

    At what time will the string break? at what position will the mass be when this happens?

    He does give a hint which to my closed mind does not help (w=v/r , a=w^2(r)

    Ohh i think he said that is was spining vertically not horizontally
    Thanks for you time
  2. jcsd
  3. Sep 30, 2006 #2


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    Homework Helper

    Start by writing down the data, and the kinematic equations (radial acceleration) for circular motion in curvilinear coordinates. Now start by analyzing the case when t=0.
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