The Concept of Potential Energy
Potential energy is defined as the energy stored in an object due to its position or arrangement. It suggests the stored capacity for doing work, often associated with the configuration of systems under conservative forces, such as gravitational and elastic forces. When a bowstring is drawn back or an object is lifted against gravity, they possess potential energy that can be converted into kinetic energy.
The gravitational potential energy (V) of an object at height (h) above the Earth’s surface is given by the formula:
where:
- m = mass of the object
- g = acceleration due to gravity (approximately 9.81 m/s²)
- h = height of the object above the reference point.
This equation underlines that work done against gravity while lifting an object is stored as potential energy. When released, this potential energy can convert into kinetic energy, allowing the object to do work as it falls, exemplified in the relation:
- K.E. = 1/2 mv² (kinetic energy at the point of impact).
The section further explains that potential energy is defined for conservative forces where the work done does not depend on the path taken, but rather on the initial and final positions only. It introduces the concept of conservative forces, noting that gravitational and elastic (spring) forces can be associated with potential energy, while friction is an example of a non-conservative force. Overall, understanding potential energy forms a cornerstone in the study of energy conservation, working power, and mechanical systems.