Spinning top in International Space Station?

Question

Recently, the first Malaysian Astronaut has conducted an experiment on which a spinning top will keep spinning in the space station...

I am kinda curious on this experiment..
My question is, Since there is air inside the space station, there should be air resistance acting on the top, right?? so, the top should stop moving after a while, isn't it??
If the top keeps spinning due to MICROGRAVITY, how?? Please explain why a top will keep spinning and even picks up speed on its own under microgravity condition... in brief, how does microgravity influence the non stop motion of the spinning top??

Thank you

aero_engr ... i can't quite understand about the part on the spinning axis of the spacecraft and the top... if the top spins in the same direction as the spacecraft, it will pick up speed?? if this is what you meant.. then isn't the top supposed to slow down when it is spinning in the opposite direction with the spacecraft??? since the momentums of the top and the spacecraft are against each other... and a top will stop spinning after a long time is due to the friction between the tip of the top and the upward force that is acting on the top??

Sorry for bothering... and thanks for your previous reply.. appreciate it..

Answer 1

Hi Fiddley -

Interesting. The air friction will eventually slow the top down, and the micro gravity will eventually make it fall over, as full gravity does on the earth's surface. However, since the effects of gravity are greatly reduced, the friction at the the point of the top, which is proportional to the normal force resulting from the weight, will be reduced, so the top will spin longer. As the spacecraft spins, the top spins inside it. So the angular momentum of the top has a component due to the top and another component due to the spacecraft. If the orientation of the spacecraft changes (i.e. the axis of rotation moves) then the top will keep spinning about it's original axis. If the top started spinning in the same axis as the spacecraft, this may result in the top speeding up relative to the spacecraft, which has - in effect- slowed down about that axis, while the top still has the angular momentum component of the spacecraft about it's original axis.

Here's one way to think about it:

A skater performs a spinning maneuver on a small ice rink. She spins at a constant rate for a brief period. Now let's place her ice rink onto a spinning carousel in the same direction. She spins at the same rate relative to the rink and the carousel, but she is spinning twice as fast relative to the ground. Now if the carousel slows down or stops (in the case of the spacecraft, it may just spin about a different axis), then the skater will continue to spin at her original rate because her angular momentum is conserved and there is nothing to put the brakes on her like there is on the carousel, so she will spin at the same speed relative to the ground, but faster relative to the carousel.

Of course, this means that if she is spinning opposite the direction of the carousel, then she will appear to stand still (relative to the ground) whether the carousel is moving or not. This assumes minimal friction between the skater and the ice while she is spinning. Note that to get up to spin speed, she has to use friction by digging her blades into the ice, which is how she picks up the extra angular momentum in the first place. But once she is spinning, the friction is near zero (like the top in microgravity) and the angular momentum is conserved.

Answer 2

With an eternal magnet DC motor (like from a battery powered toy) this might paintings extreme-high quality. An AC motor is plenty much less probably to paintings, in huge-unfold operation the magnetic field that makes an AC motor paintings is produced by potential of using the electrical energy going into it, so if no potential is going into it there is not any magnetic filed to make it act as a generator, actual there's a sprint stray magnetism or there are techniques of having all of it all started with a pulse of outdoors potential, in spite of the undeniable fact that the PM DC motor may well be least complicated . in short,confident you are able to desire to apply a motor for a generator yet no longer "basically any motor"