All AP Physics 1 Resources
Example Questions
Example Question #1 : Waves And Velocity
A major earthquake about 600km off the coast of California occurs at 9:28 AM. If you are 800km from the epicenter and feel the earthquake at 10:43 AM, how fast are the waves traveling?
To determine the velocity of the created waves, we need to know how quickly they cover a certain distance. The problem statement tells us that the covered distance is 800km. From the given time differences, we know that it takes 1 hour and 15 minutes to cover that distance. We will need to convert this to seconds:
Now we can calculate the speed of the waves:
Example Question #4 : Waves And Velocity
On a piano, the note known as "middle C" has a frequency of roughly 262 hertz.
The coldest temperature ever recorded on Earth was . At this temperature, sound travels at in air.
If Carol plays middle C on a piano at this temperature, what will the sound's wavelength be?
For any wave,
We know that the frequency of middle C is 262 hertz, and we also know that the speed of sound is . Therefore:
Solving for wavelength yields
Example Question #3 : Waves And Velocity
A light wave has a wavelength of . What is its frequency?
The equation relaing velocity, wavelength, and frequency is:
.
Solving for frequency,
Example Question #6 : Waves And Velocity
If we wanted to double wave velocity, but could only change frequency and wavelength by the same factor, by what factor would we have to change both frequency and wavelength?
We would have to change both frequency and wavelength by a factor of
We would have to change both frequency and wavelength by a factor of
We would have to change both frequency and wavelength by a factor of
We would have to change both frequency and wavelength by a factor of
We would have to change both frequency and wavelength by a factor of
Wave speed is related to wavelength and frequency by:
, where is wavelength and is frequency.
If we wanted to change by 2, and change both and by the same factor , we could set this up as:
If we isolated just the factors by which we're changing the wave speed,
We'd have to change both wavelength and frequency by
Example Question #1 : Waves And Velocity
What is the speed of light when passed through glass with an index of refraction of 2?
The equation for the speed of light through materials of different indices of refraction is given by the following equation:
Solve for velocity:
Example Question #53 : Waves
waves are hitting the side of the pier in a regular fashion. waves hit the pier during , and the waves are between crests, calculate the velocity of the waves.
We can calculate the velocity of a wave if we know the wavelength and the frequency of the wave by the following equation,
We are told , and can calculate the frequency
Therefore, we can find the velocity of the waves,
Example Question #1 : Waves And Velocity
A wave emitter is set to a frequency of . It is found that there is between anti-nodes of the waves created by this instrument. What is the speed of the waves as measured by this experiment?
The distance between each anti-node in a standing wave is only half a wavelength, so we need to multiply the distance measured between anti-nodes by 2. Multiply the wavelength by the frequency to get the speed of the wave.
We need to remember to convert our centimeters to meters and our megaHertz to Hertz so the units work out:
Example Question #1 : Waves And Velocity
Determine the wavelength of a wave traveling through a material with tension 10N, a linear mass density of , and frequency 10Hz.
None of these
We need to utilize two equations for this question. The first of which is:
Here, is wave speed, is tension force of the material, and is linear density. The othe equation we need to use is:
Here, is wave speed, is wavelength and is frequency.
In our case:
plug in known values and solve for wave speed.
Solve the second equation for .
Plug in known values and solve for wavelength.
Example Question #1 : Longitudinal And Transverse Waves
At a local concert, a speaker is set up to produce low-pitched base sounds with a frequency range of 20Hz to 200Hz, which can be modeled as sine waves. In a simplified model, the sound waves the speaker produces can be modeled as a cylindrical pipe with one end closed that travel through the air at a velocity of , where T is the temperature in °C.
What type of waves are sound waves?
Transverse
Electromagnetic
Gravitational
Longitudinal
Longitudinal
Sound waves are longitudinal waves, meaning that the waves propagate by compression and rarefaction of their medium. They are termed longitudinal waves because the particles in the medium through which the wave travels (air molecules in our case) oscillate parallel to the direction of motion. Alternatively, transverse waves oscillate perpendicular to the direction of motion. Common examples of transverse waves include light and, to a basic approximation, waves on the ocean.
Example Question #1 : Longitudinal And Transverse Waves
Which of these is an example of a longitudinal wave?
A wave produced by a rope oscillating in a plane
X-rays
Visible light
Microwaves
A sound wave
A sound wave
Longitudinal waves transmit energy by compressing and rarefacting the medium in the same direction as they are traveling. Sounds waves are longitudinal waves and travel by compressing the air through which they travel, causing vibration.
Light, X-rays, and microwaves are all examples of electromagnetic waves; even if you cannot recall if they are longitudinal or transverse, they are all members of the same phenomenon and will have the same type of wave transmission. Transverse waves are generated by oscillation within a plane perpendicular to the direction of motion. Oscillating a rope is a transverse wave, as it is not compressing in the direction of motion.
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