Modern Electricity and Magnetism, Theoretically and Practically Considered

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Excerpt from Modern Electricity and Magnetism, Theoretically and Practically Considered: Being the Chapter on Electricity, From the Elements of Natural Philosophy The rate of doing work is called power. A horse power represents the ability to perform 550 foot-pounds in a second or foot-pounds in a minute. 1t equals about 746 X ergs per second. Energy is the power of doing work. A mass of matter in motion is able to overcome resistance, or to do work, by virtue of its weight and velocity. Energy of motion, like that of a falling hammer, or of ¿owing Water, is called kinetic energy. But matter often has a supply of possible energy by virtue of a position of advantage. Thus a bent bow, the raised weights of a clock or the water in a high reservoir, has a power of doing work by reason of its position alone. Such energy is called potential energy. It is evident that potential energy is easily converted into kinetic energy and vice versa. Both of these kinds of energy may pertain to masses of matter, as in the illustrations just given, or to the molecules of matter. The energy of vibrating molecules (molecular kinetic energy) does the work of the steam engine and in the case of the expansion of metals by heat, is practi cally irresistible. We shall have much to do with molec ular energy in the following pages. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.