What is Energy? Some Preliminary Physics

E. C. Pielou

in The Energy of Nature

Published by University of Chicago Press

Published in print May 2001 | ISBN: 9780226668062
Published online February 2013 | e-ISBN: 9780226668055 | DOI:
What is Energy? Some Preliminary Physics

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This chapter addresses the question: What is energy? It discusses the concept of work, energy conversions, potential energy (PE), and kinetic energy. Energy results from two kinds of forces. One kind, exemplified by gravity and elasticity, is called a conservative force; its salient feature is that it can be stored as gravitational PE and elastic PE. A system in which the only forces acting are conservative forces never runs down. The other kind of force, exemplified by friction and air resistance, is nonconservative. When nonconservative forces are operating, either alone or in combination with conservative ones, a system inevitably runs down. Nonconservative forces produce heat, and the heat can never spontaneously turn back into another kind of energy.

Keywords: work; energy conversions; potential energy; kinetic energy; gravity; elasticity; conservative force; nonconservative force

Chapter.  3168 words.  Illustrated.

Subjects: Biological Sciences

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