Situation: Two sandbags are attached by a rope to a spindle suspended off the ground 15 feet. When one sandbag is raised to the top and dropped it propels the other sandbag up. When the second sandbag reaches the top it falls and pulls the first sandbag back up. Assume the rope is short enough so that neither sandbag touchest the ground. The process continues, back and forth Questions: 1) Can the sand bags be made of a certain weight so that the force generated by one falling, pulling the other up and vis versa be continued, to infinity, all other things being equal. 2) If yes to questions 1, what is the weight of the weight of the sandbags which will allow this? I appreciate any help on this. Thanks.