P114 high school physics: 2 same objects on a smooth plane, a light spring is compressed in the middle, and the two hands are pressed to keep it still at the beginning A release both hands at the same time, the total momentum of the system is always 0 B put the left hand first, then the right hand, the total momentum is not balanced C put left hand first, then right hand, total momentum left D whenever the spring is released, the total momentum of the system remains unchanged, but not necessarily zero, as long as the spring is released and the original length is restored Which is right or wrong and why wrong

P114 high school physics: 2 same objects on a smooth plane, a light spring is compressed in the middle, and the two hands are pressed to keep it still at the beginning A release both hands at the same time, the total momentum of the system is always 0 B put the left hand first, then the right hand, the total momentum is not balanced C put left hand first, then right hand, total momentum left D whenever the spring is released, the total momentum of the system remains unchanged, but not necessarily zero, as long as the spring is released and the original length is restored Which is right or wrong and why wrong

The system is free from external force, momentum is conserved, and the total momentum is always zero. B when the left hand is released, the speed of the left ball increases to the left, and the right ball is stationary. The system is pushed by the right hand, momentum is not conserved, and the total momentum is left