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amstrad
2005-Mar-29, 04:32 PM
I have two questions regarding forces acting on rotating bodies:

1) Why does the action of applying a force to a rotating body manifest itself 90 degrees from where the force is applied. What is so special about the 90 degrees? It seems to me that the direction of the resultant force would depend on the amount of momentum in the body (i.e. the speed of rotation).

2) I read that a gyroscope precesses due to the constant force of gravity. If that is the case then why does the Earth precess? Is it due to gravitational influence of the Moon or the Sun?

Russ
2005-Mar-29, 04:35 PM
I have two questions regarding forces acting on rotating bodies:

1) Why does the action of applying a force to a rotating body manifest itself 90 degrees from where the force is applied. What is so special about the 90 degrees? It seems to me that the direction of the resultant force would depend on the amount of momentum in the body (i.e. the speed of rotation).

It's the average of the force vectors.


2) I read that a gyroscope precesses due to the constant force of gravity. If that is the case then why does the Earth precess? Is it due to gravitational influence of the Moon or the Sun?

Both.