A body undergoing a constant acceleration at 90 deg to its direction of travel will travel in a circle. Radius of the circular path is determined by a combination of the bodies velocity and the magnitude of the force. (Sorry Horace, I can't take the time to quantify all this with numbers at this time) Thus a body in orbit must have sufficient velocity to counteract the effects of gravity at that orbital radius. We call this free-fall because the body accelerates (falls) freely with gravity.
Due to Newton's second law, the body in circular motion must exert an equal force upon the source of it's acceleration. In the case of a centrifuge, the body presses against the outside of the chamber. In the case of gravitational orbit, the mass of the body exerts a small gravitational pull upon the mass it is orbiting.
The human body feels aceleration by means of the strain placed on its tissues by inertia. In freefall every cell is accelerating at the same rate, and so there is no strain, thus the body feels no weight.
Weight is the force a body exerts on some supporting structure to counter the force of gravity.
In free-fall there is no weight, because there is no need (nor mechanism) to counter the action of gravity upon the body.
Orbit is the balance between gravity (acceleration) and velocity, not between 2 opposing forces.
Harry Veeder <[EMAIL PROTECTED]> wrote:
<snip>
All this flows from _your_ force analysis of orbital motion. I think it is a
mistaken analysis because it is based on an analogy between orbital motion
and a body in a centrifuge. A body orbits the earth because it is in
free fall. There is simply no outward force associated with that sort of
motion. The bottom line is mechanical systems do not accurately model
gravitational systems.<snip>
Harry
Merlyn
Magickal Engineer and Technical Metaphysicist
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