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Homework Help: Circular motion

  1. Sep 2, 2003 #1
    some eggs are placed in a basket. the basket is safely rotated in a vertical plane so that the eggs describe a circle of radius 1 metre. what is the least speed at the top of the circle at which the eggs must move? the ans is 3.2m/s

    in this question, i managed to determine the forces present...the weight, centripetal force, i know i am suppose to form 2 equations and solve it, but i have absolutely no idea how to do it...

    i could only obtain one eqn: mv*2/r=mg-reaction (at the top of the rotation)
    at the bottom it would simply be mv*2/r=reaction-mg

    but how do you solve this and obtain the least speed?
    are there any other eqn?
  2. jcsd
  3. Sep 2, 2003 #2


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    Science Advisor

    How do you "know" you are supposed to form 2 equations?

    Actually your formula is correct. The point is that "least speed" at which the eggs will not fall is the one at which they become "weightless"- at which there is NO reaction.

    The equation you need to solve is mv^2/r= mg.
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