Exam 15: Wave Motion

A musical pitch is played at 60 dB. Another is played that sounds four times as loud. The sound intensity level of the second pitch is

A police car siren emits a sound at 600 Hz. If an observer moves toward the source at 50 km/hr and hears a siren frequency of 678 Hz, calculate the speed of the police car and whether it is approaching or receding from the observer (assume the speed of sound in air = 343 m/s).

In a seismic event, two types of waves are created, a P-wave (longitudinal) and an S-wave (transverse). The waves travel at speeds of 8 km/s and 5 km/s respectively. At a monitoring station, a P-wave is observed 10 s before the S-wave. How far is the seismic activity from the station? Assume that the waves travel in a straight line.

A passenger car traveling due east at 53.6 m/s passes a truck traveling due east at 13.4 m/s. After the car passes, the horn on the truck is blown at a frequency of 350 Hz. The speed of sound in air is 335 m/s. The frequency heard by the driver of the car is

From the figure above, you can conclude that

You have a rope that is 10 m long and has a mass of 0.2 kg. In addition, you have an oscillator that can generate a 5 Hz wave with an amplitude of 10 cm. What should the tension in the rope be if you need to transmit 10 W of power along the rope?

A traveling wave passes a point of observation. At this point, the time between successive crests is 0.2 s. Which of the following statements can be justified?

As a wave moves to the right in an elastic rope, a sequence of pictures (1 through 6) is taken at intervals of one second. An arrow points out a particle that is attached to the rope. If the width of the picture is 8 cm, this wave has a period of

If you were to reduce the frequency of a wave on a string by a factor of 2 while keeping the speed and amplitude of the wave constant, the rate at which energy is delivered by the wave would

The particle displacement in a simple harmonic wave is given by y(x, t) = 2 sin 4 $\pi$ (t + x/8), Where the units are SI. A graph of particle displacement as a function of position at T = 0.5s would include points

We can hear sounds that are produced around a corner but cannot see light that is produced around a corner because

A train traveling at 90 km/h is blowing its whistle at 440 Hz as it crosses a level crossing. You are waiting at the crossing and hear the pitch of the whistle change as the train passes you. The sound you hear changes from a frequency of _____ to a frequency of _____. (Take the speed of sound to be 340 m/s.)

Which of the following statements is true?

A string under tension carries transverse waves traveling at speed v. If the same string is under four times the tension, what is the wave speed?

An oscillator tuned to a frequency of 1 kHz is dropped from a tall building. How does the frequency picked up by a stationary observer at the top of the building change with time?

A piano wire has a tension of 650 N and a mass per unit length of 0.060 g/cm. What is the speed of waves on this wire?

If you were to double the amplitude and halve the frequency of a wave on a string while keeping the amplitude of the wave constant, the rate at which energy is delivered by the wave would

The extent to which waves diffract when they encounter an obstacle or aperture depends on

When a dense fog blanket an area at night, you can often hear traffic noises coming from a distance highway or jets taking off from an airport several miles away. The reason is because

A stationary ship generates a sound signal at the bow and has a receiver system at the stern of the ship 100 m away. The difference in time between the signal arriving at the stern traveling directly through the air and the signal reflected from the sea bottom is 0.5 second. If the velocity of sound in air is 331 m/s and in water is 1435 m/s, calculate the depth of water below the ship.