6 - Waves Flashcards
Wave=
*Transverse waves=
*Longitudinal wave=
is the transfer of momentum and energy from one point to another.
-mechanical–> obey laws of classical physics and require some medium through which to travel.
is one in which the medium is displaced perpendicularly to the direction of wave propagation, such as waves on a string
(sound wave) is one in which the medium is displaced parallel to the direction of wave propagation, such as a sound wave in air.
- electromagnetic
- matter
Wavelength (gamma)=
Frequency (f)=
is measured from any point in the wave to the point where the wave begins to repeat itself.
of a wave is the number of wavelengths that pass a fixed point in one second. Measured in hertz (Hz) or cycles per second.
Period (t)=
Amplitude (A)=
the reciprocal of frequency
.of a wave is its maximum displacement from zero. Amplitude is always positive.
**V = F(gamma)
T = 1/f**
-Velocity of the wave is dictated by what?
Two aspects of the medium affect the velocity:
1)
2)
- the medium is travels through.
1) the medium’s resistance to change in shape (elasticity)
2) the medium’s resistance to change in motion (inertia)
- for a gas, veloctiy increases with?
- greater elasticity of a medium means the faster it? Which stores what kind of energy(both elasticity and inertia?)
- Velocity is constant in a?
- Velocity of sound waves are limited?
- with temperature
- snaps back into position moving the wave along Elasticity stores potential energy/inertial stores kinetic energy
- constant nondispersive mediums
- limited by the average speed of the molecules within that gas. But move more quickly through hot rather than cold gases.
Intensity (I)=
power is the rate at which a wave transfers energy. Intensity increases with the square of the amplitude and the square of the frequency for all waves.
** I = 1/2pw^2A^2v**
Intensity level (b)=
*If the intensity increases by a factor of 10, then the decibels increase by
artificial scale which allows us to logarithmically scale the intensity of sounds. Units are in decibels (dB).
** B = 10 log I/Io**
the addition of 10 dBs.
Phase=
Constructive interference=
Destructive interference=
of a wave relates to its wavelength, frequency, and place and time of origin.
occurs when the sum of the displacements results in greater displacement.
occurs when the sum of the displacements results in a smaller displacement.
Beats=
- pitch correlates to?
- When a wave transfer from one medium to the next,what changes and what stays the same?
occur when two waves with slightly different frequencies are superimposed.
** F beat= |f1-f2|**
- pitch correlates to frequency
- When a wave transfer from one medium to the next, the wavelength changes and the frequency remains the same.
Node=
Antinodes=
Standing wave=
the point at which they collide.
the points at which there is maximum constructive interference
where the node is still, but the antinodes are moving up and down violently.
Harmonic Series=
- first harmonic (fundamental wavelength)=
- second harmonic=
a list of the wavelengths from largest to smallest of the possible standing waves for a given situation.
is the longest wavelength
created by adding another node.
Resonate=
Resonance=
standing waves described above cause the string to vibrate at its natural frequency or resonant frequency.
the condition where the natural frequency and the driving frequency are equal.
Simple harmonic motion=
-Pendulum=
which means that it’s a motion that creates a sinusoidal function in time
is another apparatus that simulates simple harmonic motion.
Doppler effect=
results because waves are unaffected by the speed of the source which produces them.
(delta)f _ = v _ and (delta)wavelength = v
fs c wavelength{s} c
\*c is not necessarily the speed of light
*when the source and observer are approaching each other, the wavelength
*for objects moving in the same direction at the same speed there is no
shortens creating a blue shift, when they are separate a red shift is created.
Doppler effect; the relative velocity is zero, so the change in frequency is zero.
