CALCULUS Understanding Its Concepts and Methods

Contents >> Index >> Force

A force is an external cause responsible for a change of a physical system. It can be thought of as something which, when acting alone, causes an object to accelerate. Gravity and magnetism are examples of forces. Force is a basic mathematical concept from which other concepts, such work and pressure, are derived.

Force is a vector—it has magnitude and direction. Forces can be added together using the parallelogram of force. When two forces act on an object, the resulting force is the vector sum of the original forces. The magnitude of the vector sum varies from zero to the sum of the magnitudes of the two forces, depending on the angle between their lines of action. If the two forces are equal, but opposite, they sum to zero, with the result that the object remains at rest or moves with a constant velocity.

As well as being added, forces can be can also be broken down into components. For example, a horizontal force pointing northeast can be split into two forces, one pointing north, and one pointing east. Summing these component forces using vector addition yields the original force.

Copyright © 2006 Darel Hardy, Fred Richman, Carol Walker, Robert Wisner. All rights reserved. Except upon the express prior permission in writing, from the authors, no part of this work may be reproduced, transcribed, stored electronically, or transmitted in any form by any method.