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.
The center of mass of an object is a point where, for purposes of measurements, all of the object's mass is imagined to be concentrated. It is also the point at which an object will balance on a single support or spin around if thrown into the air.
Knowing where the center of mass is located becomes particularly useful when calculating the motion of a body as it is acted upon by external forces. A perfectly symmetrical ball thrown through the air will travel in an arc, or parabola. This motion can be easily tracked with the naked eye or mathematically. But, for instance, if we throw a hammer into the air, it will wobble and spin, and appear not to travel in a parabolic motion. If we track the end of the hammer on its journey, it will be mathematically very complicated. There is, however, a location (the center of mass) that follows a smooth parabolic path.
In a perfectly symmetrical object, such as a barbell with equal weights on each end, the center of mass is easy to find: it is in the middle of the bar, at the exact midpoint between the two weights.
If we replace the weight on one side with one twice as heavy, the center of mass shifts towards the more massive end of the barbell. The new center of mass is 2/3 of the way from the light end to the heavy end. This is the point at which the barbell would balance on a sawhorse. To calculate the center of mass in the lopsided barbell, we find the sum of all the segments of mass of the object multiplied by the position of each segment of mass, divided by the entire mass of the object. The center of mass may not even reside inside the object: It is between the legs of a chair and in the center of a hoop.