Elastic potential energy
The definition of potential energy named two routes. Everything so far has followed the first. Here is the second.
Figure to be added
Elastic potential energy
When a force is applied to a rubber band or a bow and its length is increased, its shape changes, and the work done in doing so is stored in the band or the bow as potential energy. This is called elastic potential energy.
The same idea, a different store
Both kinds are filled by doing work and both give that work back when released. What differs is where the energy is kept.
Gravitational
Filled by working against gravity. Released by letting the object fall.
Elastic
Filled by working against the material's own resistance to being deformed. Released by letting it return to its original shape.
Where you have met it
- A drawn bow, which sends an arrow when released.
- A catapult's stretched rubber, which throws a stone.
- A wound clock spring, which drives the hands for hours.
Position or shape — either will store it
Potential energy is stored either by raising an object or by deforming it. Only the first kind is calculated with m g h.