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Salt Shaker on a Lazy Susan, magnitude of force

  1. Sep 29, 2011 #1
    Mischievous Joey likes to play with his family's lazy susan (this drives Mom crazy because it is an antique). He puts the salt shaker near the edge and tries to spin the tray at a speed so that the shaker just barely goes around without slipping off. Joey finds that the shaker just barely stays on when the turntable is making one complete turn every two seconds. Joey's older sister measures the mass of the shaker to be 87 grams. She also measures the radius of the turntable to be 0.22 m, and she is able to calculate that the speed of the shaker as it successfully goes around in a circle is 0.6908 m/s.

    What is the magnitude of the horizontal part of the contact force on the shaker by the turntable?

    i am so lost, can someone please help me to get this problem started?? i thought i needed to find the acceleration of the salt shaker and used 0 as my starting velocity, but when i went to find the force i didnt come up with the right answer.
    Last edited: Sep 29, 2011
  2. jcsd
  3. Sep 29, 2011 #2
    A body moving at uniform speed in a circle must have a centripetal acc.
    Do you know the expression for this acc?
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