Most springs do not simply obey Hooke’s law because they are constructed to have an initial tension, which must be overcome before normal elongation occurs. This property, well known to engineers, is universally neglected in elementary physics courses. In particular, the standard simple harmonic motion experiment omits any discussion of this property while implicitly taking into account, to some extent, its consequences. A simple, linear model of initial tension could be used to justify the usual experimental procedure. The simplicity of the model renders its analysis accessible to introductory students.
References
1.
For example, http://science.clemson.edu/physics/labs/labs/124/shm/index.html; http://web2.utc.edu/~pbs273/181Springconstlab.pdf;
Lab Schedule—Physics 201, Washington State University
, https://hub.wsu.edu/physlabs/physics-201; and Phys-1140 Course Information (Sp 2019), University of Colorado Boulder, https://www.colorado.edu/physics/phys1140.2.
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A falling block with a spring attached to the bottom involves such a force.
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2019
American Association of Physics Teachers
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