# Does a toy top weigh less when it is spinning?

I am under the understanding that a toy top will weigh less when it is spinning. The Russians made a spinning type transport back in the 70s to lessen its payload over the tundra. Is this an effective way to beat gravity?

• Short answer: no. Long answer: noooooooooooooooo. – Mitchell Aug 10 '12 at 2:49
• E=mc**2, ergo adding kinetic energy makes the top slightly heavier. – Ignacio Vazquez-Abrams Aug 10 '12 at 3:21
• Very, very, slightly. Unless you're exceptionally strong. :) – elifino Dec 11 '15 at 2:59

No.

A top can offer stability like in a gyroscope, but it does not in any way reduce the mass of an object.

Some applications of a gyroscope are useful for transport, however. The popular Segway scooters use them to measure how far/fast it is tilting forward or backward and drives the wheels to compensate.. Similarly, motorcycles take advantage of the gyroscopic motion of their wheels to stay upright. Over the tundra, I could conceive of a gyroscope being used to keep a sled tilted up so that it is heavier on the backside and thus doesn't get caught toe up in the snow, but it would not reduce the mass at all. On the contrary, the mass of the gyroscopic device is just more to haul around.

• The Segway uses mems gyroscopes to measure how far/fast it is tilting forward or backward and drives the wheels to compensate. It doesn't use a gyroscope force to stabilise it – Martin Beckett Aug 10 '12 at 14:02
• It's unfortunate that accelerometers, north-seeking gyros and reaction-wheels all get called gyroscopes. – Martin Beckett Aug 10 '12 at 16:07

To a certain extent yes, if you take aerodynamics into account. Specially made top can deflect air to provide a lift force. Exaggerated example is a helicopter. A better example though is Frisbee.

But it's not because the mass reduced or something is done to gravity, it's just a force exerted by surrounding air.

By the way, George, provide a reference to that Russian transport so we could see what's the matter with it.

• You're talking about weight. – Bernhard Aug 10 '12 at 17:19
• @Bernhard so was the questioner. – kleingordon Aug 10 '12 at 19:03
• @YR, its been years since i read the article about the Russians, in a book like popular science or mechanics, and it must have been aprox 1972, i will try a search to find it. Thanks for your answer but has anyone actually weighed a spinning top using weigh scales? – George Jones Aug 11 '12 at 1:54
• @kleingordon It was tagged mass, and the whole question does not clearly show what he meant. – Bernhard Aug 11 '12 at 7:32
• George, I'm sure someone did it, but I never encountered these works. You can do it yourself. Buy a toy gyroscope and appropriate weights. If the phenomena is strong enough to be considered to put on a transoprt you'll be able to measure it even with such a cheap gadgets. By the way certain effect of spinning is used to increase weight, the effect is used in millstones (en.wikipedia.org/wiki/Millstone). Beforehand, no, it could not be reversed to decrease weight. – Yrogirg Aug 11 '12 at 10:47

## protected by Emilio PisantyNov 12 '17 at 13:38

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