The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Velocity is the rate of change of an object’s distance with time.
The velocity of an object includes specification of its direction. For example, the velocity of a car may be 60 miles per hour (mph) (96.6 kph) west, or 5.45 yd (5 m/sec) downward. (Such quantities, which have both a magnitude and a direction, are called vectors.) The value of the velocity, without specifying the direction, is called the speed. Speed is what is displayed on a car’s speedometer.
An object’s velocity is always relative to an observer. That is, an observer along the side of a road might see a car go by with a certain velocity, say, 60 mph to the east. But a different observer in a car also going 60 mph to the east would see the first car as being at rest relative to him--it would have no velocity. The two observers, ground and car, each think themselves to be at rest, and only see velocity relative to them. But the velocity values are very different.
Albert Einstein built on this concept of relative velocities to construct his special theory of relativity. This theory, which has been verified and is an accepted principle in physics, holds that no object can travel faster than a limiting speed, which is the speed of light. Einstein showed that unexpected things occur as objects travel with speeds near that of light--their mass increases, they shrink in size, etc.
Angular velocity is the velocity of an object traveling in a circle. It is measured by the amount of angle an object sweeps out in a certain period of time. An object that takes 1 second to travel around a circle, such as a rock swung around on the end of a rope, has an angular velocity of 1 revolution per second, or 360 degrees per second. The direction of the object changes as it moves around--at any instant its direction is tangential to the circle.
Velocity is related to other basic concepts of physics. The mass of an object multiplied by its velocity is the object's momentum, also a vector. The rate of change of the velocity with time is the acceleration, also a vector quantity. An object with a constant velocity thus has no acceleration.