Quote Originally Posted by Ralphxyz View Post
How does a bag drop in zero gravity?
The short answer is: It isn't in zero gravity. Mathematically, the distortion of space-time we call gravity extends from the parent mass all the way out to infinity decreasing as the inverse square as one moves away from the mass.

The rotational motion of the satellite exactly balances the force of gravity at the satellite's height. If the speed of the bag exactly matches that of the ISS, it will orbit along with it. Change the speed of the bag slightly (e.g., as by losing grip while moving it) and it will want to move to a new orbit consistent with its new velocity. Once it reaches that new orbit height it will remain there in orbit.