Question

1. The fact that a trumpet and a saxaphone sound different when playing the same fundamental frequency is best explained by which concept listed below?

a. The Doppler Effect
b. Sound wave reflection
c. Beats
d. Timbre

2. A single-frequency air horn (f = 800 Hz) is sounded by a rider in a roller coaster moving toward you at 47 m/s as you stand next to the track. What frequency do you hear? Assume the speed of sound to be 340 m/s.

a. 928 Hz
b. 1004 Hz
c. 1109 Hz
d. 832 Hz

3. Using the same scenario as question #2, now assume that you are a rider on a second coaster moving toward the sender. You both have the same speed relative to the ground. You hear a frequency of 1207 Hz. What is the frequency of the sender's air-horn?

a. 752 Hz
b. 834 Hz
c. 888 Hz
d. 914 Hz

Answer 1

Ans

1- d. Timber

2- a. 928 Hz

3- d. 914 Hz

Explanation

1-d)-In simple terms, timbre is what makes a particular musical sound have a different sound from another, even when they have the same pitch and loudness.

While the Doppler Effect distinguished same sound when there is relative motion between source and observer. It relates change in frequency of sound wave appear in case of relative motion.

Sound wave reflection - when sound back come back after striking any strong surface. Used for calculating speed of sound or distance between object and observer.

While beat in music theory is basic unit of time, the pulse (regularly repeating event), of mensural level.

2-a) Doppler effect will work here.

Here C is velocity of wave in medium (340m/s) while fo (800Hz) is frequency of wave emitted from source and f is frequency observed by observer. Vr (0m/s) is velocity of reciever relative to medium and Vs (47m/s) velocity of source relative to medium.

Hence. . Source reaches observer frequency will be higher he observed and - sign will we consider.

=>. f= 928.32 Hz

3- d) 914 Hz

Now

=> fo = 1207 * 293/387 = 913.826 Hz or 914 Hz