You are working for a plumber who is laying very long sections of copper pipe for a large building project. he spends a lot of time measuring the lengths of the sections with a measuring tape. you suggest a faster way to measure the length. you know that the speed of a one-dimensional compressional wave traveling along a copper pipe is 3.56 km/s. you suggest that a worker give a sharp hammer blow at one end of the pipe. using an oscilloscope app on your smartphone, you will measure the time interval δt between the arrival of the two sound waves due to the blow: one through the 20.0°c air and the other through the pipe.
a) derive an equation that can be used to calculate the length (l) of the pipe.
b) you measure a time δt=127 ms between the arrivals of the pulses. determine the length of the pipe.
c) your smartphone claims an accuracy of 1% in measuring time intervals. how many centimeters of uncertainty does your measurement have?