A guitarist is tuning his guitar using harmonics. When in tune, the sixth string (low E string) should be at a frequency of 82.41 Hz, and the fourth string (D string) should be at a frequency of 146.83 Hz. Determine the frequency difference between the fourth harmonic of the sixth string and the third harmonic of the fourth string.

A collimated sound beam of frequency 340 Hz enters the open end of a U-shaped pipe, as shown in the figure. The experiment is done at room temperature. The two parallel parts of the U-shaped tube are separated by a distance of 15 cm and connected by a round turn. The parallel tubes have an initial length of 65 cm. The length could be extended by the same amount, l, on each side. The maximum extension is 65 cm. On the other open end, a sound level meter is used to detect the transmitted waves. Calculate the possible values of l for which the sound level meter picks up the highest level of sound.

An open-ended tube producing a second harmonic frequency of 380 Hz is suddenly closed at one end. Calculate the first harmonic wavelength (λ) of the stopped tube.

Musicians often tune their instruments before a performance to ensure accurate pitch. Suppose a guitarist tunes his instrument by adjusting two strings to oscillate precisely at 250 Hz. Later, he notices that one of the strings is slightly out of tune and increases its tension. This change results in four beats per second being audible when the two strings vibrate simultaneously. Determine the new frequency of the string with the increased tension.

A saxophonist detects six beats per second when playing a note on their saxophone and comparing it with a 784 Hz chime. Through adjustments in the position of the mouthpiece (pulling it out), the saxophonist is able to align the frequency with the chime. Determine the initial frequency of the saxophonist's played note.

An orchestral harpist is fine-tuning his harp to ensure that the notes are accurately tuned. When in tune, note C should be at a frequency of 523 Hz, and note G should be at 784 Hz. Compared with a properly tuned C string, the harpist finds the G string's tension to be somewhat low, so he tightens the string in small increments until it reaches the desired level. Determine the frequency of the G string when the harpist detects a difference of five beats per second.

An ambulance behind a wide-load truck driving in the same direction emits an alert tone at 1500 Hz. The ambulance moves at 28.0 m/s and the truck moves at 14.0 m/s. Determine the wavelength of the waves reflected by the truck's load measured relative to the ambulance. 

A car driving at 15 m/s hoots at a frequency of 410 Hz in the motionless air. Determine the frequency heard by a driver in another car moving at 25 m/s in the opposite direction and approaching the hooting car. 

A whistle (supplied by a stream of air) emitting sound at 3.00 kHz is fixed to a rotating blade 1.60 m from the axis of rotation. The blade spins in a horizontal circle at 360 rpm. If the sound undergoes the Doppler effect, work out the greatest and least frequencies detected by an observer.

On a string, as shown, two wave pulses move with equal speed of 8.0 cm/s towards each other. At the start of the observation, the pulses are 20 cm apart between their peaks. Draw the wave pulses' positions at t = 1.0 s, t = 1.5 s, and t = 2.0 s.