Question about the tether scene from the movie "Gravity" In the movie there's a scene where two astronauts are joined together by a rope. One is accelerating to pull the other. The astronaut would accelerate, the rope would tense and give a jerk to the other astronaut. Then the rope would loosen again until the accelerating astronaut gained enough velocity to tense the rope again, giving another jerk. If something had very little mass, I believe the rope would simply remain tense. My question is, how do you determine if the rope remains tense or loosens? How much more velocity does the astronaut being pulled gain over the accelerating astronaut such that they loosen the rope?