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Physics doesn't always come in the form of books. It also comes in the form of toys.

So, I came across this fascinating toy that spins two minutes straight when given a spin. I got a chance to use it, but couldn't figure out where to thrust it. Every point that I tried on gave the impression that there was a better position somewhere else. From then, I have been left thinking,

Where to thrust the spinner, so as to make it attain the maximum angular velocity possible ?

I appreciate any ideas, but if we could project an answer supported by experimental data and mathematics for this, it would be great!

fidget spinner lines of action

Here are some positions that I have tried spinning it:

Near the center of the iron armor:

The spinner attained the maximum velocity fast, so I guess it is very near to our answer.

Near the neck of the spinner:

Great force had to be applied, but the speed attained was fairly large.

Along the side of the limbs of the spinner:

Less force needed to be applied, but no appreciable increment in velocity.

(More creative methods are welcome!!)

Now the force needn't always be tangential as I had shown above.

You can think of changing the angle of line of action of the force, too.

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  • $\begingroup$ and spun round and round the merry-go-round... $\endgroup$ – Mozibur Ullah Jan 16 at 17:07
  • $\begingroup$ What are you spinning it with? If it's a finger, then the force exerted at different locations might not be the same based on how easy it is to push there. $\endgroup$ – probably_someone Jan 16 at 18:11
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Assuming you are spinning with the same linear speed, the angular speed would be the highest at the smallest radius. Thus (2) is the correct answer.

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Where to thrust the spinner, so as to make it attain the maximum angular velocity possible ?

I don't understand this question. What makes you think that there is a 'maximum' angular velocity? Classically speaking, there isn't one, though of course empirically speaking there is one and this is dependent on the composition of the object.

Moreover, any point will do, as angular velocity attained is positively correlated with applied thrust; so increasing thrust, will increase the the angular velocity.

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