# Why won't this reactionless drive idea work (motor with a moving weight in space)

I know people will say it violates many laws of motion and conservation but could anyone explain why it is so? It's NOT a question about free energy.

Imagine a motor in space. It has an arm (rod) attached to it. At the end of the arm there's a ball (weight) attached to it. The motor produces a circular motion. So the motor is the center and the rod is the radius. To the ball there is a rope attached which connects to the rod aswell, but the rod keeps the ball in place. The rope is longer than the radius. The rod has a realease mechanism to let the ball go. When the ball is released, it disconnects from the rod and flies away in a tangent. Then the ball flies for some distance until it is stopped by the rope.

Does the sudden stopping of the ball by the rope make the motor move off its place and head in a single direction?

Is there any opposite reaction force to the direction of the moving ball on the moment that it is released?

Is there an opposite reaction force somewhere that makes this impossible and cancels out any potential movement causing forces all together?

Is it possible that this can make the system as a whole (motor, ball, rope and rod) move in a single direction without reaction mass being expelled and without external forces acting upon it? And if so, will this system stop moving when it catches up with its ball?

I appreciate help a lot.

• "The motor produces a circular motion. So the motor is the center and the rod is the radius." Well, it depends on how heavy the motor is compared to the ball at the end of the rod. The system will (I think?) rotate about its center of mass, which in general will not be located at the motor, but will be somewhere between the motor and the ball. So the motor will already be moving around as is. To simplify matters, you can consider the system to be a dumbbell (motor and ball) and see how the math works out. – DumpsterDoofus Apr 15 '14 at 19:21
• Ok I think the motor should have the largest mass, thus making the center of mass as close to the motor as possible. That way, I can call the motor the center turning point where the dumbell rotates around. – Arundel Apr 15 '14 at 19:34