Module 6—Work and Energy
Lesson Summary
In this lesson you explored the following questions:
- What is work?
- What are gravitational potential energy and elastic potential energy?
- What is kinetic energy?
- How do gravitational potential energy, elastic potential energy, and kinetic energy interact during a bungee jump?
Work is a measure of the amount of energy transferred when a force acts over a given displacement. It is the product of the magnitude of the applied force and the displacement of the object in the direction of that force.
Gravitational potential energy is the energy of an object due to its position above the surface of Earth.
Elastic potential energy is energy produced or consumed by an object that is altered from its standard shape without permanent deformation.
Kinetic energy is the energy due to the motion of an object.
A bungee jump starts with gravitational potential energy. On the way down, the energy is converted to kinetic energy and, finally, to elastic potential energy at the very bottom. On the way up, the process is reversed. With each bounce, some energy is lost from the system, and eventually the motion stops.
Lesson Glossary
elastic potential energy: energy stored in a spring or elastic object that has been compressed or stretched
gravitational potential energy: the potential energy of an object due to its height above Earth
Hooke's law: the amount of stretch (deformation) of an elastic object is proportional to the force applied to deform it
kinetic energy: energy that a body has because of its motion
mechanical system: a system that has both potential and kinetic energy
work: the energy transferred by a force to a moving object; the product of a force and the distance through which the force is applied