Physics conudrum

[Japher]

direction of axis? wtf is that? I'm drunk and that doesn't even make sense!

think of a) center of gravity of the object in questionm b) the fact that spin is actually an acceleration in the direction of that center of gravity c) real gravity effects the spin d) force is only a component of torque

[Urban Ranger]

Originally posted by Japher
direction of axis? wtf is that? I'm drunk and that doesn't even make sense!

The axis points to a certain direction in three dimensional space, does it not?

If you aren't drunk maybe it makes more sense

Originally posted by Japher
b) the fact that spin is actually an acceleration in the direction of that center of gravity

Um, now that doesn't make sense. The spin is an angular acceleration around the axis and the axis goes through the centre of mass. I don't see how that is "in the direction" of the centre of mass, though.

[KrazyHorse]

Because of the conservation of angular momentum.

A gyroscope's angular momentum vector points along its axis, so changing that axis changes its angular momentum. if the gyroscope's disk is a uniform plate of radius R and mass M rotating at angular velocity w then it has angular momentum L = wMR^2/2

To change the angle of the axis by a differential angle dTheta the change in angular momentum imparted to the gyroscope must be LdTheta. Thus the gyroscope provides an angular velocity-dependent restorative torque of LdTheta/dt

[aneeshm]

The baseball thing can be explained by Bernoulli's theorem ( different velocities on different sides causing a pressure difference , making the ball curve ) . I don't know about the bullet .

[KrazyHorse]

Originally posted by aneeshm
The baseball thing can be explained by Bernoulli's theorem ( different velocities on different sides causing a pressure difference , making the ball curve )

Not quite

[aneeshm]

What ?

[KrazyHorse]

Since the motion of the air relative to the surface of the moving baseball is actually faster on the side whose rotation is in the direction of flight than on the side whose rotation is against the direction of flight, the naive application of the Bernoulli effect would predict that the ball would actually break opposite the direction of rotation rather than in the direction of rotation.

[Provost Harrison]

See what you've done now Zkribbler? Shame on you

[TheStinger]

Nah

Clever pitchers actually curve space around the ball which travels straight.

[Zkribbler]

Originally posted by Provost Harrison
See what you've done now Zkribbler? Shame on you

I know. I'd shoot myself...but with the spin on the bullet, I'd probably miss.