A student decides to test the speed of sound through wood using a wooden ruler. The student rests the ruler on a desk with half of its length protruding off the desk edge. The student then holds one end in place and strikes the protruding end with his other hand, creating a musical sound, and counts the number of vibrations of the ruler. Explain why the student would not be able to measure the speed of sound through wood using this method.

Video Transcript

This is College Physics Answers with Shaun Dychko. A student rests a ruler on the edge of a table and with half of it hanging off the edge (so here's the ruler... half of it's hanging off the edge) and then they strike the overhanging end with their hand and then count how quickly the ruler is bouncing up and down off the table. And this is a way of measuring the frequency of sound produced by the ruler because you are measuring the frequency with which it's hitting the table and that's what's being measured not the speed of sound propagating through the wood. So this is measuring frequency, which is f... it's not measuring v.