Question 1

A bat, flying at 5.00 m/s, emits a chirp at 40.0 kHz. If this sound pulse is reflected by a wall, what is the frequency of the echo received by the bat? (vsound = 340 m/s.)

Accepted Answer

The answer of A bat, flying at 5.00 m/s, emits...

Question 2

A circus performer stretches a tightrope between two towers. He strikes one end of the rope and sends a wave along it toward the other tower. He notes that it takes 0.8 s for the wave to travel the 20 m to the opposite tower. If one metre of the rope has a mass of 0.35 kg, find the tension in the tightrope.

Accepted Answer

The answer of A circus performer stretches a tightrope between...

Question 3

Bats can detect small objects such as insects that are of a size approximately that of one wavelength. If bats emit a chirp at a frequency of 60 kHz, and the speed of sound in air is 340 m/s, what is the smallest size insect they can detect?

Accepted Answer

The answer of Bats can detect small objects such as...

Question 4

When a workman strikes a steel pipeline with a hammer, he generates both longitudinal and transverse waves. The two types of reflected waves return 2.4 s apart. How far away is the reflection point? (For steel, vL = 6.2 km/s, vT = 3.2 km/s)

Accepted Answer

The answer of When a workman strikes a steel pipeline...

Question 5

If a plane is flying at a speed so that the apex half-angle of its shockwave is 30 $\degree$, what is its speed if the speed of sound is 320 m/s?

Accepted Answer

The formula for finding the speed of a plane generating a shock wave with a given apex half-angle is:
v = M × a, where v is the speed of the plane, M is the Mach number, and a is the speed of sound.
The half-angle of the shockwave can be used to find the Mach angle using the formula:
sin(Mach angle) = 1/M
Thus, sin(30°) = 1/M, which gives M = 2
Therefore, v = 2 × 320 m/s = 640 m/s, which is answer choice B.

Question 6

The intensity level of an orchestra is 85 dB. A single violin achieves a level of 70 dB. How does the intensity of the sound of the full orchestra compare with that of the violin?

Accepted Answer

The answer of The intensity level of an orchestra is...

Question 7

A microphone in the ocean is sensitive to the sounds emitted by dolphins. To produce a usable signal, sound waves striking the microphone must have an intensity of 1.02 *10-11 W/m². If dolphins emit sounds with a power of 0.049 9 W, how far away can a dolphin be and still be heard? Disregard absorption of sound waves by the water.

Accepted Answer

The answer of A microphone in the ocean is sensitive...

Question 8

An aircraft travelling at half the speed of sound emits sound at a frequency of 5000 Hz. At what frequency does a stationary listener hear the sound as the plane approaches, and after it passes by? Assume the aircraft is not flying very high.

Accepted Answer

The answer of An aircraft travelling at half the speed...

Question 9

If the breakers at a beach are separated by 5.0 m and hit shore with a frequency of 0.20 Hz, with what speed are they travelling?

Accepted Answer

The answer of If the breakers at a beach are...

Question 10

If a supersonic plane is flying at increasing speed as the temperature decreases, what happens to the Mach number in this instance?

Accepted Answer

As temperature decreases, the speed of sound also decreases. Therefore, in order to maintain the same speed relative to the speed of sound, the airplane must increase its speed. This means that the Mach number, which is the ratio of the airplane's speed to the speed of sound, will increase.

Quiz 17: Wave Motion

A bat, flying at 5.00 m/s, emits a chirp at 40.0 kHz. If this sound pulse is reflected by a wall, what is the frequency of the echo received by the bat? (vsound = 340 m/s.)

Bats can detect small objects such as insects that are of a size approximately that of one wavelength. If bats emit a chirp at a frequency of 60 kHz, and the speed of sound in air is 340 m/s, what is the smallest size insect they can detect?

When a workman strikes a steel pipeline with a hammer, he generates both longitudinal and transverse waves. The two types of reflected waves return 2.4 s apart. How far away is the reflection point? (For steel, vL = 6.2 km/s, vT = 3.2 km/s)

If a plane is flying at a speed so that the apex half-angle of its shockwave is 30 $\degree$ , what is its speed if the speed of sound is 320 m/s?

The intensity level of an orchestra is 85 dB. A single violin achieves a level of 70 dB. How does the intensity of the sound of the full orchestra compare with that of the violin?

An aircraft travelling at half the speed of sound emits sound at a frequency of 5000 Hz. At what frequency does a stationary listener hear the sound as the plane approaches, and after it passes by? Assume the aircraft is not flying very high.

If the breakers at a beach are separated by 5.0 m and hit shore with a frequency of 0.20 Hz, with what speed are they travelling?

If a supersonic plane is flying at increasing speed as the temperature decreases, what happens to the Mach number in this instance?

Quiz 17: Wave Motion

A bat, flying at 5.00 m/s, emits a chirp at 40.0 kHz. If this sound pulse is reflected by a wall, what is the frequency of the echo received by the bat? (vsound = 340 m/s.)

Bats can detect small objects such as insects that are of a size approximately that of one wavelength. If bats emit a chirp at a frequency of 60 kHz, and the speed of sound in air is 340 m/s, what is the smallest size insect they can detect?

When a workman strikes a steel pipeline with a hammer, he generates both longitudinal and transverse waves. The two types of reflected waves return 2.4 s apart. How far away is the reflection point? (For steel, vL = 6.2 km/s, vT = 3.2 km/s)

If a plane is flying at a speed so that the apex half-angle of its shockwave is 30 °\degree° , what is its speed if the speed of sound is 320 m/s?

The intensity level of an orchestra is 85 dB. A single violin achieves a level of 70 dB. How does the intensity of the sound of the full orchestra compare with that of the violin?

An aircraft travelling at half the speed of sound emits sound at a frequency of 5000 Hz. At what frequency does a stationary listener hear the sound as the plane approaches, and after it passes by? Assume the aircraft is not flying very high.

If the breakers at a beach are separated by 5.0 m and hit shore with a frequency of 0.20 Hz, with what speed are they travelling?

If a supersonic plane is flying at increasing speed as the temperature decreases, what happens to the Mach number in this instance?

If a plane is flying at a speed so that the apex half-angle of its shockwave is 30 $\degree$ , what is its speed if the speed of sound is 320 m/s?