In how many different directions can a sphere spin at the same time?

Question

Is there a limit to the number of directions? You may need to try to mentally visualise this, its tricky.

Answer 1

At any one point in time, there is exactly one axis of rotation. That axis can change over time, but the instantaneous rotation is always around a single axis.

Answer 2

1

Answer 3

At least three.

You have the sphere's rotation about the rotational axis.

The sphere's rotation creates an angular momentum vector. The angular momentum vector can rotate as well. This is called precession.

You also have an angular velocity vector, which does not necessarily have to be in alignment with the angular momentum vector. If the two vectors are offset, the angular velocity vector rotates about the angular momentum vector. This is called nutation.

Precession is caused by some outside force acting on the system. Gravity affecting the spin of a bicycle tire hanging from a rope for example.

Nutation is caused by losing rotational kinetic energy due to internal causes. While the total energy may stay constant, energy can change form - from kinetic energy to potential energy for example. Even within kinetic energy, you have different types. Heat is just the kinetic energy caused by the internal 'jiggling' of molecules - if they jiggle faster (heat up), the energy has to come from somewhere and you can lose rotational kinetic energy.

Edit: If the gyroscopes on planes rotate on the same axis no matter how the plane moves, then it's a very old navigation system. I've never heard of navigational gyros that work like that. Normally, you look at the rest of scubaspud's post to understand how gyros work. The gyro will try to maintain the same axis, but will be forced to move with the plane. A spring could measure the amount of force needed to keep the gyro in alignment with the plane. That would be an old system, as well. Now a days, electromagnets are used in place of springs, but the technique is the same - you measure the amount of force the gyro resists having its axis changed.

Answer 4

2

Answer 5

Just ONE, if I understand your question correctly. The axis of spin can be any direction, but a sphere can only "spin" around one axis at a time. There is a (non-trivial) mathematical theorem underlying this:

THEOREM: Any rigid motion in 3-dimensions is a rotation about some axis.

(Well, technically you need say "orientation preserving rigid motion which fixes the origin" in the theorem above. Otherwise you could have translations and reflections for instance. However, these restrictions are implicit in the idea of a physical "rotation".)

Answer 6

certainly, the rotation of the Earth does not have a function interior the technology of its gravitational field as that comes fullyyt as a effect of its mass. The rotation does despite if impact the technology of its magnetic field. the theory at the back of using rotation of a spacecraft to generate "man made gravity" is via the fact gadgets would be pressed against interior the wall of the rotating craft because of resistance of inertial forces lots comparable to once you will desire to pull in a weighed string swung over your head to avert the load from flying off tangential to its around direction. This stress will develop proportionally with greater advantageous radius from the middle of rotation with an identical rotational era. In different words, while pondering a rotating sphere the stress would be nicely suited close to the "equator" or factor equidistant from the rotating poles. So the rotating sphere or disc does not certainly generate gravity, yet a stress which would be a pragmatic substitution in an otherwise weightless environment and confident, sufficient stress must be generated this manner to approximate 1G or the conventional stress of gravity on the earth.

Answer 7

Only in one direction unless some external force is causing a change of axis.

Earth spins on direction (counterclockwise looking down on it from the north pole) There is however another effect on Earth (tides, gravitational forces, etc.) that causes precessional rotation (like that of a top)... the axis of spin varies a few degrees over a period of 10s of thousands of years. One hunderd centuries from now the, axis of Earth will not point to the North Star (it really doesn't now, but it's close). It will then point several degrees off.

Answer 8

Its got only one axis of rotation the X, Y and Z axi have nothing to do with rotation but are used for describing the position of the object. Time should be ignored along with the other 7 unmentioned dimensions. If you attempt to change the direction of spin then the single rotational axis moves, another rotation axis is not created.

Answer 9

For a perfectly uniform sphere, the mathematical proof says only one axis at a time. In the real world, nothing is perfect, and as a result, a sphere can actually spin on any number of axes simultaneously- this is called "tumble".

Typically you can model tumble using two or three axes to any degree of precision. So a good, practical answer is three.

Answer 10

Only 2

Answer 11

I'm guessing 4. I say that because I'm thinking of the earth, 1st is it's spinning for day and night 2nd it also rotates at the poles, (the poles don't stay in a fixed position hope that makes sense), 3rd it spins around the sun and 4th the solar system spins in the universe.
Well I'm probably all wrong but hey at least I get 2 points!