Assignment:
Question 1. Imagine two symmetrical pulses that are identical in every way, except tht one is inverted. These pulses are moving toward each other on a rope in opposite directions. What happens to the energy of the rope at the instant of complete cancellation?
Question 2. In the real world, a pulse sent down a very long, taut rope diminishes in amplitude and ultimately vanishes. Describe what's happening in terms of Conservation of Energy.
Multiple choice:
Question 1. A periodic wave passes an observer, who records tht there is a time of .5 s between crests. (a) the frequency is .5 Hz (b) the speed is .5 m/s (c) the wavelength is .5 m (d) the period is .5 s (e) none of these. Explain your choice.
Question 2. For a harmonic wave of a certain type in a given medium, doubling the frequency has the effect of: (a) halving the speed (b) halving the wavelength (c) doubling the amplitude (d) doubling the period (e) none of these. Explain your answer.
Question 3. Quite generally, doubling the amplitude of a wave: (a) doubles the frequency (b) halves the period (c) quadurpled the energy (d) doubles the speed (e) none of these. Explain your choice.
Problem
Question 1. A long metal rod is stuck by a vibrating hammer in such a way that a compression wave with a wavelength of 4.3 m travels down its length at a speed of 3.5 km/s. What was the frequency of the vibration?
Question 2. Imagine a sinusoidal presssure wave for which the distance between successive maxima is 2.25 m. If exactly 10 such peaks pass a microphone each 1.00 s, what is the speed of the wave?
Question 3. A person standing at one side of a playing field on a cold winter night emits a brief yell. The short acoustical wavetrain returns 1.00 s later as an echo having "bounced off" a distant dormitory. Approximately how far away was the building?
Question 4. A low-frequency loudspeaker is called a woofer. At what frequency will a tone have a wavelength equal to the diameter of a 15-inch woofer? Take the speed of sound to be 344 m/s.
Question 5. The speed of sound in ether (25 deg C, 1 atm) is 976 m/s. What is the wavelength in ether produced by a tuning fork oscillating at 1000 Hz?
Question 6. Suppose that a tuning fork in air, where the speed of sound is 343 m/s, produces a tone having a wavelength of 0.7795 m. The fork is immersed in acetone and then tapped. How long a wave will be created in the liquid given the acetone (20 deg C, 1 atm) supports sound waves tht travel at 1203 m/s.