Physics test Ch. 25 & 26 Flashcards
3 things that go into us hearing sound?
We hear sound from the molecules bouncing, the eardrum receives it and sends signals to nerves through little hairs that are disturbed
What is the text book def. of vibrations?
A wiggle in time
What is the Law of the Pendelum?
Whatever the starting point, bc of the friction, air resistance, etc, the pendulum will never reach the original height again
What is the period of a wave?
Amount of time to get from the starting place, across, and back to the starting place
What is Simple Harmonic Motion?
Motion of going back and forth and back and forth and… Like a pendulum…when you hit a tuning fork and it shakes
What is the Amplitude of a wave?
Magnitude of the crest and trough (would be the same) (Max distance from 0)
What is the Wavelength? what is it measured in?
often in meters, from any two identical parts of the wave (Distance from one place to another)
What is Frequency? what is it measured in?
The number of vibrations in the given amount of time (how often it is going through its period) usually per second
List some electromagnetic waves
Electromagnetic Waves: Gamma, X, UV, and radio, all have different wavelengths and frequencies (measured in hertz)
what is the equation for wave speed?
Wave speed= wavelength x frequency
list in order of speed: air, metal, water
Fastest in metal, then water, and slowest in air
What is moving when a wave is being created?
The energy is what is actually moving
What is wave speed measured in?
m/s
Long wavelength = ____ frequency
low
fast wavelength=____ frequency
high
Can Transverse waves draw sine curves?
no
What motion makes a Longitudinal wave?
up and down in a straight line
Longitudinal wave is ________ to the direction of the wave
parallel
What is interference?
When waves begin to “get in touch” with each other
What kind of interference amplifies the waves?
Constructive
What kind of interference cancel each other out
destructive
What is a standing wave?
Transverse waves where there is an attachment point at one end
What is a node?
Point that never goes up or down in a standing wave
More nodes=_______ frequency= ________ wavelength
higher, decreasing
Antinodes: Point that _________
moves
Doppler Effect:
Apparent change in frequency due to the location of the source compared to the receiver of that wave.
What color shift does the universe have?
red
What is a Bow wave?
when the object our races the wave (planes and boats)
What shape is a shock wave?
A 3-dimensional wave
All sounds are produced by ________
vibrations
What determines pitch?
how the hairs in your ear vibrate
Low pitch=______ frequency
low
The range we can typically hear is between _____ (low pitch) and ________ (high pitch) hertz
20=20,000
Infrasonic:
Less than 20 hertz (Too low to hear)
Ultrasonic:
More than 20,000 hertz (Too high to hear)
Can sound travel in space? light?
Sound no, light yes
What is loudness measured in?
Decibels
Amplitude:
The difference between the median and the top of the wave
____________ measures how high a wave is reaching above the midpoint (in decibels)
Oscilloscope
Forced vibration:
when you force a vibration onto another object, a tuning fork
Everything has a natural frequency based on _______ & _______
shape and material
Resonance:
forced vibration at the object’s natural frequency causes an increase in amplitude
When at a concert, venues will sell certain seats for more because they sound better. What causes some seats to sound worse? (on the test)
dead spots
Where did a bridge collapse from wind?
Tacoma, Washington
__________ lost a bunch of soldiers when they marched over a bridge and it collapsed
Great Britain
When a pebble is dropped it makes ___ waves usually
3
Where does sound travel faster, LA or ATL? Why?
More moisture in the air in Atl makes it so sound travels faster here than in LA
