Re: [Phys-L] pendulum in free fall

[stefan jeglinski <jeglin@4pi.com>]

Thanks Tom,

Yes see Carl's correction for the obvious error on my part.

In fact this question grew out of your related case comment. When 
cutting the cable at the end of swing, both the elevator observers and 
the ground observers see respectively a bob at rest or a bob falling in 
lockstep with the rest of the elevator cab.

Stefan Jeglinski


On 1/6/25 8:21 AM, Tom Van Baak wrote:
> Stefan,
>
> A pendulum in zero-g is more like an orbit, a free hand of a clock, a 
> Ferris wheel. SHM no longer applies.
>
> So if g vanishes instantly the Ferris wheel has rotational speed equal 
> to the lateral speed V of the pendulum at that instant. The new period 
> is simply C/V where C is the circumference of the circle (2 pi L).
>
> There is no difference in behavior depending on the observer.
>
> A related interesting case is if the cable is cut, not at the instant 
> the pendulum reaches mid-swing, but at end of swing. In that case the 
> string, the bob, and the elevator all drop as if freeze-frame.
>
> /tvb
>
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