Turn in your answers to the following problems below. As always, make sure to show all of your work.
1. Sound waves travel through an aluminum bar at a speed of 1400 m/s. If the frequency of the sound wave is 1000 Hz, what is the distance between crests on a sound wave traveling through aluminum?
2. An airplane flies horizontally at a constant speed, piloted by rescuers who are searching for a disabled boat. When the plane is directly above the boat, the boat's crew blows a loud horn. By the time plane's sound detector receives the horn's sound, the plane has traveled a distance equal to one-half its altitude above the ocean. If it takes the sound 4.00s to reach the plane, determine
a) the altitude of the plane, and
b) its speed, in m/s. What is its speed in knots (nautical miles per hour)?
3. Estimate the wavelength of a 20,000 Hz sound wave, which is near the upper limit of audibility for humans. Assume air at standard temperature and pressure.
4)An organ pipe is a closed-ended air column. If its bottom note has a frequency of 20 Hz, then how long is the column? Assume standard temperature and pressure.
5.The sound of a truck horn, observed when the truck is stationary, is 440 Hz. A drunk is sitting in the middle of the road at night. He sees the truck's headlights, and hears a 480 Hz horn. How rapidly is the truck approaching him, in m/s2? In mph?