An ideal spring is hung vertically from the ceiling. When a $2\mathrm{.}0-kg$ mass hangs at rest from it$,$ the spring is extended $6\mathrm{.}0$ cm from its relaxed length. An upward external force is then applied to the block to move it upward a distance of $10$ cm $.$ While the block is being moved by the force, the work done by the spring is