30. * Equation Jeopardy 1 Tell everything you can about the wave described by the equations below. Ey = (2.4 × 10³ NC) cos [2x (15 x 10-15 s B₂ (1.5. 5+ S = (8.0 × 10-4 T) cos[2 ( 15× 10-15 s - x 4.5 × 10-7 m)] 4.5 × 10-7 m)]

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 t between the arrival of the two sound waves due to the blow: one through the 20.0C air and the other through the pipe. (a) To measure the length, you must derive an equation that relates the length L of the pipe numerically to the time interval t. (b) You measure a time interval of t = 127 ms between the arrivals of the pulses and, from this value, determine the length of the pipe. (c) Your smartphone app claims an accuracy of 1.0% in measuring time intervals. So you calculate by how many centimeters your calculation of the length might be in error.

A tuning fork generates sound waves with a frequency of 246 Hz. The waves travel in opposite directions along a hallway, are reflected by end walls, and return. The hallway is 47.0 m long and the tuning fork is located 14.0 m from one end. What is the phase difference between the reflected waves when they meet at the tuning fork? The speed of sound in air is 343 m/s.

How do sound vibrations of atoms differ from thermal motion?