At 08:29 AM 1/14/2005 -0800, you wrote: >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
Dr Johnson was walking down a narrow lane one day. Houses on either side were of the old fashioned type with upper stories projecting almost half way across the street. >From opposite upper story windows two women were leaning out and having a violent argument. Dr Johnson paused for a moment and contemplated the scene before him. Turning to his companion he observed. "Those women will never agree. They are arguing from different premises." ;-) Cheers Grimer
