# Acceleration

## Force And Acceleration

Before the time of Sir Isaac Newton, the concept of force was unknown. Newton's second law was a simple equation and an insight that significantly affected physics in the seventeenth century as well as today. In the second law, given any object of mass (m), the acceleration (a) given to that object is directly proportional to the net force (F) acting on the object and inversely proportional to the mass of the object. Symbolically, this means a = F/m or in its more familiar form F = ma. In order for acceleration to occur, a net force must act on an object.

## Resources

### Books

Cohen, I. Bernard. Introduction to Newton's Principia. Lincoln, NE: iUniverse, 1999.

Galilei, Galileo. Dialogues Concerning Two New Sciences. Translated by H. Crew and A. DiSalvo. Glendale, CA: Prometheus Books, 1991.

Goldstein, Herbert, Charles P. Poole, and John L. Safko. Classical Mechanics. 3rd ed. New York, Prentice Hall, 2002.

Hewitt, Paul. Conceptual Physics. Englewood Cliffs, NJ: Prentice Hall, 2001.

Meriam, J.L., and L.G. Kraige. Engineering Mechanics, Dynamics. 5th ed. New York: John Wiley & Sons, 2002.

Methods of Motion: An Introduction to Mechanics. Washington, DC: National Science Teachers Association, 1992.

Serway, Raymond, Jerry S. Faughn, and Clement J. Moses. College Physics. 6th ed. Pacific Grove, CA: Brooks/Cole, 2002.

Kenneth L. Frazier

## KEY TERMS

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Acceleration

—The rate at which the velocity of an object changes over time.

Circular acceleration

—Acceleration in which the direction of motion is changing.

Force

—Influence exerted on an object by an outside agent which produces an acceleration changing the object's state of motion.

"G" forces

—The apparent increase in body weight due to rapid acceleration; a force of 2 "G"s means that a body feels a force of twice its body weight acting on it.

Gravity

—The special acceleration of 9.81 m/s2 exerted by the attraction of the mass of the Earth on nearby objects at Earth's surface.

Linear acceleration

—Acceleration in which the magnitude (velocity) of the motion is changing.

Mass

—A measure of the quantity of matter in an object.

Vector

—A quantity or term that can be expressed in terms of both magnitude (a number) and a direction.

Velocity

—The speed and direction of a moving object.

Weightlessness

—A condition caused by accelerating freely toward the Earth at the same rate as gravity and not feeling the usual effects of weight.