When students perform Experiment 3, “Standing Waves on a String,” in Advanced Physics with Vernier - Beyond Mechanics (PHYS-ABM), they set up standing waves using a braided string attached to the Power Amplifier Accessory Speaker (PAAS-PAMP) driven by the Power Amplifier (PAMP). The resonant frequencies at which the standing wave is formed depend on the tension in the string and the linear mass density of the string. The Accessory Speaker ships with both an elastic cord and lightweight braided string; each has different resonant frequencies.

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In 2014, the lightweight, braided string that shipped with the Accessory Speaker was changed. Because the new string has a different linear mass density than the old string, the resonant frequencies of the string changed. This change means that the values in the data table in the Teacher Information section (page 3-5I) and the corresponding graphs (Figures 4 and 5) will not match data measured using the new string.

The linear mass density of the new lightweight, braided string is 2.2 g/m. Note, however, that sometimes the density will change due to manufacturing or sourcing variations, and the linear mass density should be verified.