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Finding the safe rotational speed of a carousel?

  1. Apr 12, 2010 #1
    Hi,

    I'm currently working on a project for a braking system of a carousel. Basically in order to start designing the brake I need to know what the maximum rotational speed of the carousel should be. The max diameter of the surface will be 2 meters and the maximum speed at the periphery should not be greater than 5m/s from standards. However as the diameter gets smaller and smaller the rotational speed will still increase taking these standards.

    What I want to do is work out the speed that will throw someone off the carousel using maybe the centrifugal force or some such method. I assume that this is most likely on the outside of the circle? (i.e. max radius of 1). I was wondering if anyone had any suggestions as to how I would calculate this?

    Any help would be greatly appreciated.

    Mark.
     
  2. jcsd
  3. Apr 12, 2010 #2

    PhanthomJay

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    Assuming the person is not holding onto a pole (or a horse), then the critical case is when the person is standing at the edge of the circle, where the centripetal acceleration is the greatest, and where the only force capable of providing that acceleration is the friction force between the floor of the carousel and the person's shoes (or feet, if barefoot, etc.). I imagine that the safe speed of a carousel assumes a rather low friction value, especially in consideration of the unseated ticket taker worker. In your example, using your 5m/s tangential speed at the periphery, the centripetal acceleration for a 1 m radius would be v^2/r = 25m/s^2, implying a friction coefficient of 2.5, which is way higher than the friction coefficient between the feet and the surface, meaning that the person would fly off at that speed. So I would question that 5m/s value you got from "Standards".
     
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