Exam 16: Wave Motion

A truck moving at 36 m/s passes a police car moving at 45 m/s in the opposite direction. If the frequency of the siren is 500 Hz relative to the police car, what is the frequency heard by an observer in the truck after the police car passes the truck? (The speed of sound in air is 343 m/s.)

The equation is the same as

Which of the following does not have a precise definition in terms of the physical properties of sound waves?

The Young's modulus for aluminum is 7.02 × 10¹⁰ N/m². If the speed of sound in aluminum is measured to be 5.10 km/s, find its density (in kg/m³).

The wave equation is written down in an exam as From dimensional considerations we see that

Which of the following is a solution to the wave equation, ?

Calculate the pressure amplitude (in N/m²) of a 500 Hz sound wave in helium if the displacement amplitude is equal to 5.0 × 10−⁸ m. (ρ = 0.179 kg/m³, v = 972 m/s.)

If y = 0.02 sin (30x − 400t) (SI units) and if the mass density of the string on which the wave propagates is 0.005 kg/m, then the transmitted power is

To transmit four times as much energy per unit time along a string, you can

Exhibit 16-2 The figure below shows a sine wave on a string at one instant of time. Use this exhibit to answer the following question(s). -Refer to Exhibit 16-2. Which of the graphs below shows a wave where the wavelength is twice as large?

How fast (in m/s) is the Concorde moving if it reaches Mach 1.5? (The speed of sound in air is 344 m/s.)

(Do not try the following: it could kill you. This question is only about a hypothetical possibility.) If you were standing below an object emitting a fixed frequency sound falling at terminal velocity, as it approached you, you would hear the sound

Exhibit 16-3 Four wave functions are given below. I.y(x, t) = 5sin(4x - 20t + 4) II.y(x, t) = 5sin(3x - 12t + 5) III.y(x, t) = 5cos(4x + 24t + 6) IV.y(x, t) = 14cos(2x - 8t + 3) Use this exhibit to answer the following question(s). -Refer to Exhibit 16-3. Rank the wave functions in order of the magnitude of the wavelengths, from least to greatest.

Exhibit 16-2 The figure below shows a sine wave on a string at one instant of time. Use this exhibit to answer the following question(s). -Refer to Exhibit 16-2. Which of the graphs below shows a wave where the frequency and wave velocity are both doubled?

Write the equation of a wave, traveling along the +x axis with an amplitude of 0.02 m, a frequency of 440 Hz, and a speed of 330 m/sec.

Transverse waves are traveling on a 1.00-m long piano string at 500 m/s. If the points of zero vibration occur at one-half wavelength (where the string is fastened at both ends), find the frequency of vibration.

A spherical wave has the form . The amplitude of the wave a distance r from the source is

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?

A spherical wave has the form . The frequency of the wave (in Hz) is

Calculate the intensity level in dB of a sound wave that has an intensity of 15 × 10−⁴ W/m².