A stretched bow.
Explanation
Potential Energy is the energy possessed by a body by virtue of its position or configuration. It is primarily classified into two types based on the cause of the stored energy:
- Gravitational Potential Energy: Energy stored due to the object's vertical position or height relative to a reference level (e.g., the ground).
- Elastic Potential Energy: Energy stored due to the deformation, distortion, or change in the shape (configuration) of an object.
Analysis of Options:
- A stone lying on a roof. A stone lying on a roof: This object possesses Gravitational Potential Energy due to its height above the ground. There is no change in its shape.
- A stretched bow. A stretched bow: This object possesses Elastic Potential Energy. The energy is stored because the bow has been deformed (stretched) from its original configuration. This stored energy is released to propel the arrow.
- A flying airplane. A flying airplane: This object possesses both Kinetic Energy (due to its velocity) and Gravitational Potential Energy (due to its altitude). It is not primarily characterized by energy due to deformation.
- Water in a dam. Water in a dam: This possesses Gravitational Potential Energy due to the height of the water level relative to the turbines or the riverbed below.
Key Takeaway: Energy derived from height or position is Gravitational Potential Energy, while energy derived from a change in shape or configuration (stretching or compressing) is Elastic Potential Energy.