@pickover The spring will contract when the string is cut, exerting an upward force on the ball. No upward force on the other ball so it hits the ground first.
@zionistsrm25517@engineers_feed Also its mass and radius to compute the torque required to make it rotate, if there were anywhere to mount it on Saturn. There isn't, the whole system is in freefall flapping in the wind. The pulley isn't turning. The rope had no reason to stay on it.
@CervidaeCider@ritam378@engineers_feed A simple pulley only redirects the force. Also basic physics probably usually assume the pulley is massless and friction-less. If it had mass, a torque would be required to make it rotate. If the axle had friction, some kinetic energy would be converted to heat.