Final answer:
The stone will move again after being stopped by a spring due to the conservation of energy in the system, where stored potential energy in the spring is reconverted back into kinetic energy.
Step-by-step explanation:
The question at hand pertains to conservation of energy within a mechanical system and whether a stone will move again after being stopped by a spring. When a stone is dropped onto a spring, and if we ignore non-conservative forces like air resistance and assume the surface is frictionless, the kinetic energy of the wagons is converted fully into potential energy stored in the spring when it compresses. Upon reaching maximum compression, the spring's stored potential energy can cause the stone to be propelled back, converting potential back into kinetic energy. Therefore, depending whether energy is conserved in the system, which in this ideal case it is, the stone will move again.
If we consider a real-life scenario where the block is attached to a spring on a frictionless surface, when the block is pushed and the spring is compressed, elastic potential energy is stored. This stored energy is the maximum when the block is at rest, just before it's released. As the spring expands, this potential energy is converted back into kinetic energy, propelling the block back. When the block crosses the point where the spring is neither compressed nor stretched, it will be moving at its maximum speed because all of the potential energy has been converted to kinetic energy.