11 Standing Waves

Justin Nandkishwar Physics Lab 1611 70122 December 1st, 2021 Lab Report Experiment 11: Standing Waves in a String Purpose The purpose of this experiment is for students to observe and understand the formation of standing waves and find the frequency of the string. Data n M + m hanger T v L λ f | f - <f>| 1 550g 539,000N 19,951.9cm/s 77.6cm 155.2cm 128.56Hz 0.13 2 140g 137,200N 10,066.3cm/s 77.6cm 77.6cm 129.72Hz 1.03 3 65g 63,700N 6,858.99cm/s 77.6cm 51.7cm 132.69Hz 4.0 4 35g 34,300N 5,033.13cm/s 77.6cm 38.8cm 129.73Hz 1.04 5 20g 19,600N 3,804.68cm/s 77.6cm 31.0cm 122.73Hz 5.96 Average < f > 128.69Hz (2) Calculate the % discrepancy between the average < f > of your data and the actual frequency fo = 120 Hz of the vibrating metal strip. 7.24% (3) Answer these questions: Q#1: What is the major reason for limiting your table to n=5, even if higher modes could be observed? The major reason for limiting the table to n=5 even if higher modes could be observed is because as you decrease the weight, the nodes will increase, and we wouldn’t have a lighter hanger to use. In addition, it would be hard to see the nodes to count when it passes 5 nodes. Q#2: Your string is similar to strings in a violin, in a piano, etc., which emit musical sounds. Did you hear some sound, and if you did, in which mode was it? If not, what should have been the main reason? (Hint: assume your hearing is perfect.) 51