6.2. Energy http://www.ck12.org
6.2 Energy
Objectives
The student will:
- Understand the relationship between work and energy
- Be able to distinguish between kinetic and potential energy
- Understand the role of friction as it pertains to work and energy
- Be able to solve problems involving kinetic and potential energy and friction.
Vocabulary
- energy:The ability to do an amount of work. Different forms of energy can do work indirectly.
- kinetic energy:Energy of an object from its motion.
- potential energy:Energy from an object’s position.
- Work-Energy Principle:The net work done on an object is equal to its change in kinetic energy.
Introduction
In the language of physics,energyis the ability to do work. Remember that we previously defined work as force
applied over distance. Doing work creates energy, and energy can be used to do work. Force and work can come
in endless forms, from nuclear to microscopic to everyday objects. Figure6.10 are some icons portraying different
types of energy. From left to right, there is a lightning bolt, a campfire, a speeding bullet, a battery, a log, and a rock
on a hill.
FIGURE 6.10
In ordinary language, only the first two are energy. However, within physics there are two kinds of energy:kinetic