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Distance and time, two fundamental quantities, are discussed early in most introductory physics courses. By dividing a change in distance by time to get velocity, and by dividing a change in velocity by time to get acceleration, two more important quantities result. With these the real world of automobiles and jet planes and applications of Newton's second law is available for interpretation from an analytical point of view. In order to get students thinking reliably about these important ideas it seems important to have direct measurements of distance and time over short enough intervals to talk sensibly about "instantaneous" velocities.



This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in

Rafert, J. B., & Nicklin, R. (1984). Velocity measurements of humans by computers. The Physics Teacher, 22(4), 213–221.

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