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Homework Help: Gyroscope experiments

  1. Nov 28, 2008 #1
    I need to do experiments to investigate the behaviour of gyroscopes but I'm not too sure what I can do.I've thought I can use a bicycle wheel and string to demonstrate precession, but I need experiments which I can take recordings down from.

    Thanks for any help!
  2. jcsd
  3. Nov 28, 2008 #2
    Re: Gyroscopes

    Hello Starlet,
    This is my first time posting, so forgive me if I sound a little inexperienced. Ok, here we go...

    The angular speed of precession can be found from the equation: speed = (wr)/(I* \omega) where r is the distance of the wheel from the pivot, w is the weight of the wheel, I is the moment of inertia of the wheel about the axis, and \omega is the angular speed of the wheel.

    The bicycle wheel mounted on an axle connected to a free pivot should be sufficient to investigate the behaviour of gyroscopes

    The dependent variable, the angular speed of the gyroscope's precession can be found simply by timing the period of one revolution of the gyroscope system.

    From the equation, there are several independent variables which one can consider, which I will leave to you to consider yourself.

  4. Nov 28, 2008 #3
    Re: Gyroscopes

    Ahhhh, I see. I'll have a look in my textbooks about this equation. We haven't done this yet. I'll have a good read about it then and on the internet too. I'll more than likely be back again within the next few days asking more questions about it...so watch out!

    Thanks a lot for your help!
  5. Nov 30, 2008 #4
    Re: Gyroscopes

    Forgive me for being so slow on such a probably simple topic, but what is the difference between the angular speed of the wheel and the angular speed of precession? I'm not too sure how to find the angular speed of the wheel.

    Also, does I=mr^2? And should I vary the angular speed of the wheel?

    So sorry again! Thanks a lot for your help
  6. Nov 30, 2008 #5
    Re: Gyroscopes

    Ah, don't mention it. Trust me, the physics of gryoscopes aren't exactly straightforward, but i'll try the best i can.

    Your first question: Well, consider a spinning top. If you observe the top axis of the top (excuse the pun), notice that it moves in a relatively slow-moving circle, the speed of which the top axis moves is the angular speed of precession. The actual speed of the spinning top is the angular speed of the top.

    In the case of the bicycle wheel on the axle, the axle will actually rotate about the pivot (at a relatively slow speed, this is the precession speed), when the bicycle wheel is rotating about the axle (this is the angular speed of the wheel).

    2nd Question: The angular speed of the wheel can be found by placing a mark on the wheel, and timing the time it takes to complete, say 10 revolutions, and taking the average period from there.

    3rd Question: I = mr^2 is an approximation, assuming that the wheel can be modelled as a hoop without the spokes. To vary I, you need to vary the size of the wheel you use, and this affects the weight too. So, these two variables must be varied together.\

    PS: If you need a comphensive explanation on how gyroscopes work, feel free to ask.
  7. Dec 1, 2008 #6
    Re: Gyroscopes

    Thanks a lot for explaining that to me. Makes a lot more sense now :)

    I've looked a lot on the internet but I think I might buy a gyroscope to help my understanding a bit more.

    Could you help me to think of any other ways which I can investigate the behaviour of gyroscopes? Either using the bicycle wheel, an actual gyroscope or something else. I'm not too sure if I can investigate nutation for example in much depth.
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