The now widespread use of microcomputers in introductory physics laboratories allows for an addendum to the traditional mass-spring-system experiment that usually culminates with the determination of the spring constant k. A sonic-motion detector can be used to create plots of position, velocity, and acceleration as functions of time and even position versus velocity. Students can then be asked to compare these plots and observe the relationships between the variables. This, however, is only the beginning. The use of features of the data-collection software allows for further and even more informative analysis.

The plot was done with Logger Pro using a motion detector attached to a LabPro interface. Vernier Software,
D. Halliday, R. Resnick, J. Walker, Fundamentals of Physics, 4th ed. (Wiley, New York, 1993), pp. 397–398.
The effective mass of a spring can be shown to be one-third of its actual mass. Adding this (m = 0.0543 kg) to the mass attached to the spring (m = 0.278 kg) gave the effective mass (m =0.332 kg) used for the system. See A.P. French, Vibrations and Waves (W.W. Norton, New York, 1971), p. 61.
Logger Pro (see Ref. 1) includes a data table from which the positions and times of the peaks were extracted.
The plot and fit were done with Graphical Analysis. Vernier Software,
Traditional experiments using plots of the period squared and position both as functions of mass were used to determine the spring constant.
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