http://www.ck12.orgCHAPTER
9 Energy
Chapter Outline
9.1 Kinetic Energy
9.2 POTENTIALENERGY
9.3 CONSERVATION OFENERGY
9.4 ELASTIC ANDINELASTICCOLLISIONS
9.5 REFERENCES
The roller coaster shown here is a perfect example of different types of energy. Energy is either “potential,” meaning
that it is stored and not yet in use, or “kinetic,” meaning that it is energy in motion or in use. Common sources of
energy include gravity, chemicals, temperature differences, and solar energy. Energy continually surrounds us and
can easily be converted from one form to another. The chemical energy of the food in your last meal, for example,
has been transformed into a different form of chemical energy in your body, and may become kinetic energy at your
soccer practice this afternoon. This roller coaster converts kinetic to potential energy, and vice versa. You will learn
about several forms of energy and how they change from one to another in this chapter.