Module 14 Quiz Flashcards
A wave with a direction of propagation that is parallel to its direction of oscillation
Longitudinal wave
Any speed that is faster than the speed of sound in the substance of interest
Supersonic speed
The sound produced as a result of an object traveling at or above Mach 1
Sonic boom
An indication of how high or low a sound is, which is primarily determined by the frequency of the sound wave
Pitch
In designing a car’s horn, the engineers test the sound of the horn and decide that its pitch is too low. To adjust the horn, should the engineers change the electronics so as to produce sound waves with longer or shorter wavelengths?
The engineers need to adjust the electronics to emit sound waves with a shorter wavelength
A sound wave has a speed of 345 m/sec and a wavelength of 500 meters. Is this wave infrasonic, sonic, or ultrasonic?
infrasonic wave (Keep the second CD open and look at explanation)
A physicist takes an alarm clock and puts it in an airtight chamber. When the chamber is sealed but still full of air, the physicist is able to hear the alarm despite the fact that he is outside of the chamber. If the physicist then uses a vacuum pump to evacuate essentially all the air out of the chamber, will the physicist still be able to hear the alarm? Why or why not?
The physicist will not be able to hear the alarm because, without air, the sound waves from the alarm have nothing through which to travel. Thus, they cannot make waves. As a result, there is no sound
Are sound waves transverse waves or longitudinal waves?
Sound waves are longitudinal waves
Sound waves are traveling through the air and suddenly run into a wall. As the sound waves travel through the wall, do they travel faster, slower, or at the same speed as when they were traveling in the air?
the sound travels faster in the wall
In the situation described above, what happens to the amplitude of the wave? Is the amplitude of the wave smaller, larger, or the same as the amplitude before the wave hit the wall?
the amplitude of the wave will be smaller
Why do jets travel at speeds of Mach 1 or higher only in sparsely populated regions?
When a jet travels at Mach 1 or higher, it creates a shock wave of air that causes a very loud boom. This boom can damage people’s ears and buildings
A guitar player is plucking on a string. If he takes his finger and pinches the string to the neck of the guitar so as to shorten the length of the string, will the pitch of the sound emitted increase, decrease, or stay the same?
the pitch will increase
You hear two musical notes. They both have the same pitch, but the first is louder than the second. If you compare the sound waves of each sound, what aspect(s) of the wave (wavelength, frequency, speed, and amplitude) would be the same? What aspect(s) would be different?
The wavelength, frequency, and speed will all be the same
The amplitudes of the waves will be different
The horn on your neighbor’s car is stuck, so it is constantly blaring. You watch your neighbor get into the car and drive away from you, heading toward the nearest place for automobile service. Compare the pitch of the horn before he starts to drive away to the pitch you hear as he is driving away from you.
the horn’s pitch is lower when it is moving away from you
You are riding your bicycle toward a stationary police car with a siren that is blaring away. Will the pitch of the siren sound lower, higher, or the same as it will sound when you actually stop your bicycle? (Assume the actual pitch of the siren stays constant.)
higher
