A rubber cord that is not stretched is pulled by a force $F$. A graph is drawn of force $F$ against extension $x$. $F$ is then raised gradually from zero, so the cord extends along path P. After that, $F$ is lowered again to zero along path Q. What does the shaded area represent?
- Athe elastic energy stored in the rubber cord
- Bthe energy that causes plastic deformation
- Cthe energy dissipated as heat
- Dthe work done to extend the rubber cord