Will the spinning gyroscope make the plumb fall slower?

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    Fall Gyroscope Spinning
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Discussion Overview

The discussion revolves around the behavior of a spinning gyroscope and its effect on the rate of fall of a plumb bob. Participants explore whether a spinning gyroscope can slow down the falling motion of the plumb bob compared to a non-spinning scenario, considering both theoretical and experimental perspectives.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes an experiment where a spinning bike wheel unwinds more slowly from a string, questioning if a similar effect occurs with a plumb bob falling alongside a spinning gyroscope.
  • Another participant suggests calculating the inertial momentum of the gyroscope, noting that spinning up a gyroscope requires force for angular acceleration.
  • Some participants argue that applying an off-axis force does not "use up" force, as all force contributes to linear and angular momentum, referencing conservation laws.
  • There is confusion regarding the mechanism described in the original post, with one participant expressing difficulty in understanding the setup and its implications.
  • Another participant interprets the setup as involving two strings wound around a spindle, suggesting that the wheel's drop rate would depend on the conversion of gravitational potential energy into rotational kinetic energy.

Areas of Agreement / Disagreement

Participants express differing views on the mechanism and effects of the spinning gyroscope on the falling plumb bob, with no consensus reached on the validity of the claims or the experimental observations.

Contextual Notes

Participants highlight potential limitations in understanding the described mechanism, with some noting that the relationship between the gyroscope's spinning and the plumb bob's fall remains unclear and may depend on specific conditions not fully articulated.

SpaceThoughts
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When winding a bike wheel up in an elastic double string in the ceiling, and then let the wheel spin vertically, it unwinds more slowly than if it was not spinning. I tried it.
But it if a spinning disk is placed in a solid construction like this (photo attached) , and can only rotate horizontally as the blue plump falls, will the plumb likewise fall more slowly than if the gyroscope was not spinning? If no, why is the gyroscope not working the same way as with the string in the ceiling?
I tried to simulate the situation in the photo with a moving front wheel of a bike, by could not detect a slower movement of the bike wheel, spinning versus not spinning.
Is that because the gyroscopic inertia (not the forces) is too small compared to the weight of the handlebars etc?
If the spinning gyroscope does slow down the falling plumb, how do I mathematically connect the speed of the wheel with the speed of the plumb? Please see my previous question.

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Calculate with the inertial momentum of the gyroscope. Spinning up a gyroscope is like a mass being accelerated; it needs to 'use' some of that force for its angular acceleration.
 
cmb said:
Spinning up a gyroscope is like a mass being accelerated; it needs to 'use' some of that force for its angular acceleration.
If you apply an off-axis force to an object, none of that force is "used up". All of the force goes into linear acceleration. That's conservation of momentum in action. All of the force (times moment arm) also goes into angular momentum. That's conservation of angular momentum in action.

Both laws apply. Both apply to the full force.

That said, I can make neither head nor tail of the mechanism described in the original post. It is word salad and an inscrutable drawing to me.
 
jbriggs444 said:
If you apply an off-axis force to an object, none of that force is "used up". All of the force goes into linear acceleration. That's conservation of momentum in action. All of the force (times moment arm) also goes into angular momentum. That's conservation of angular momentum in action.

Both laws apply. Both apply to the full force.

That said, I can make neither head nor tail of the mechanism described in the original post. It is word salad and an inscrutable drawing to me.
I took the description to mean there are two strings wound around the spindle of the wheel, and thus as the wheel falls so the wheel will spin up (hence the 'gyroscope' reference in the thread title) according to the tension in the strings.

The rate at which all that would happen would be a function of the radius of the spindle about which the strings are coiled.

Obviously, the wheel will drop slowly as the gravitational potential energy is largely converted into inertial rotational kinetic energy.

I thus took the second description to mean likewise, but that the 'gyroscope' is now fixed and the tension horizontal to a mass which can fall vertically.

If it was not 'that', then yes, forget what I said.
 

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