A mathmatical description of a wave.

The displacement (in meters) of a wave is y= 0.26 sin((pie)t-3.79(pie)x, where t is in seconds and x is in meters. (a) Is the wave traveling in the +x or-x direction? (b) What is the displacement of y when t= 38s and x=13m?

Sound Intensity

A rocket in a firework's display explodes high in the air. The sound speeds out uniformly in all directions. The intensity of the sound is 2.0 x 10^-6 W/m^2 at a distance of 120 m from the explosion. Find the distance from the source at which the intensity is 0.80 x 10^-6 W/m^2.

Decibels

The volume control on a stereo amplifier is adjusted so the sound intensity level increases from 23 to 61 dB. What is the ratio of the final sound intensiry to the original sound intensity?

Concept question

(a) When sound emerges from a loadspeaker, is the diffraction angle determined by the wavelength, the diameter of the speaker, or a combination of these two factors?(b) How is the wavelength of a sound related to its frequency ? Explain your answers. Problem The following two lists give diameters and sound frequencies for thre ...continues

Periodic waves : Calculating frequency and speed.

Suppose that 15 boxcars on a freight train pass by in a time of 12.0 seconds and each has a length of 14.0 m. (a) What is the frequency at which each boxcar passes? (b) What is the speed of the train?

Periodic waves

A longitudinal wave with a frequency of 3.0 Hz takes 1.7 seconds to travel the length of a 2.5m Slinky. Determine the wavelength of the wave.

The Speed of a Wave

A 0.75 m string is stretched so the tension is 2.3N. A transverse wave with a frequency of 150 Hz and a wavelength of 0.40 m travels on the string. What is the mass of the string?

Sound : Calculating the angular speed of a rotating disk.

A siren can be made by blowing a jet of air through 20 equally spaced holes in a rotating disk. The time it takes for successive holes to move past the air jet is the period of the sound. The siren is to produce a 2,200 Hz tone. What must be the angular speed (omega) in rad/s of the disk?

Sound Waves : Calculating the fundamental frequency of an ear canal.

Sound enters the ear, travels through the auditory canal, and reaches the eardrum. The auditory canal is approximately a tube open at only one end. The other end is closed by the eardrum. A typical length for the auditory canal in an adult is about 2.9 cm. The speed of sound is 343 m/s. What is the fundamental frequency of ...continues

Sound waves : Calculating the longest and shortest pipe lengths in a pipe organ.

The range of human hearing is roughly from twenty Hz to twenty kilohertz. Based on these limits and a value of 343 m/s for the speed of sound, what are the lengths of the longest and shortest pipes ( open at both ends and producing sound at their fundamental frequencies) that you expect to find in a pipe organ?