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!

Tetherball problem

  1. Jan 29, 2014 #1
    1. The problem statement, all variables and given/known data
    A .3 kg ball is attached to a string that is 50.0 cm in length, and completes 2 circles every second. Find the tension required to whirl the ball with the given constraints and also find the angle θ

    2. The attempt at a solution
    I only have that Ftcosθ = Mg and that mv^2/r = ftsinθ
    I don't know where to go from there since all I have is the length and mass because to find the radius it is r=Lsinθ which I cannot find without θ...
     
  2. jcsd
  3. Jan 29, 2014 #2

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    This is just an algebra problem now. You have done the physics!

    2 equations. 2 unknowns. Solve. Hint: try dividing the two equations.

    AM
     
    Last edited: Jan 29, 2014
  4. Jan 29, 2014 #3
    I have tried, it gives me (g)(r)sinθ/cosθ=v^2 which is 3 unknowns since I don't know radius, velocity, or θ
     
  5. Jan 30, 2014 #4

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    You can work out r from L and θ. θ is the downward angle that the tether makes as measured from the horizontal, so r = Lcosθ. Just substitute into your equation.

    v can be determined from the period and radius. Or you can just use mω2r for centripetal force.

    AM
     
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: Tetherball problem
  1. Tetherball Problem (Replies: 2)

  2. Sin^2 tetherball (Replies: 2)

Loading...