# Shared Flashcard Set

## Details

Chapter 14 Test
Vibrations and Waves
52
Physics
01/31/2013

Term
 What is periodic motion?
Definition
 motion that repeats itself in regular time intervals
Term
 What is simple harmonic motion?
Definition
 when the acceleration is proportional to displacement and directed toward equilibrium
Term
 ____goes the fastest at equlibrium. ____is zero at equlibrium.
Definition
 velocity; acceleration
Term
 What is the relationship between force or acceleration to displacement in SHM?
Definition
 force and acceleration are proportional to the displacement
Term
 define amplitude.
Definition
 maximum displacement from equlibrium
Term
 define frequency.
Definition
 number of vibrations per second (Hz)
Term
 define period.
Definition
 time for one vibration
Term
 How are frequency and period related?
Definition
Term
 What is Hooke's law?
Definition
 F=kx
Term
 What affects the period of a mass on a vibrating spring?
Definition
 mass and the spring constant (k)
Term
 HOw do you calculate the period or frequency of a mass vibrating on a spring?
Definition
 T=2 pi square root m/k
Term
 What affects the period of a pendulum?
Definition
 length of a string and the acceleration of gravity (g)
Term
 What is the difference between mechanical waves and electromagnetic waves?
Definition
 mechanical waves require a medium
Term
 identify three types of mechanical waves
Definition
 transverse, longitudinal, surface
Term
 Identify the parts of waves.
Definition
 crest, trough, wavelength, amplitude, compression, rarefaction
Term
 What represents the energy the waves is carrying?
Definition
 amplitude
Term
 Use the wave equation to determine the speed of a wave.
Definition
 V=frequency x wavelength
Term
 ____allows us to hear around corners.
Definition
 diffraction
Term
 Define reflection.
Definition
Term
 define refraction.
Definition
 turning of a wave as it is goes from one medium to another at an angle
Term
 define diffraction
Definition
 bending of a wave as it goes through an opening or around an edge
Term
 define interference
Definition
 when 2 waves meet, their amplitudes combine
Term
 What are the four wave interactions?
Definition
 reflection, refraction, diffraction, interference
Term
 What determines the speed of a wave?
Definition
 the elasticity and density of a medium
Term
 Waves travel faster in _____.
Definition
 solids
Term
 What happens when a wave gets to the end of a medium?
Definition
 it will reflect or transmit and change speed
Term
 What are the two types of reflections and what happens in them?
Definition
 fixed end (out of phase)--flips over completely; free end (in phase)---goes in and comes back on the same side
Term
 What is the law of reflection?
Definition
 angle of incidence=angle of reflection
Term
 How can you tell if a wave sppeds up or slows down when it enters a new medium?
Definition
 the shorter the wavelenth, the slower the wave; the longer the wavelength, the faster the wave
Term
 What affects how much diffraction will be produced?
Definition
 size of opening compared to wavelength; if the opening si big, there will be less diffraction and less curve
Term
 What difference in constructive and destructive interference?
Definition
 constructive interference builds up the amplitude; destructive interference reduces the amplitude; complete destructive interference is when the amplitude is completely gone
Term
 What is a node?
Definition
Term
 What is a standing wave and what conditions produce it?
Definition
 a wave that looks like it's standing there vibrating; it's produced when 2 waves with the same amplitude and frequency are traveling in opposite direction
Term
 What is a wave?
Definition
 a disturbance that transfers energy without transferring matter
Term
 a mechanical wave requires what type of medium?
Definition
 elastic medium
Term
 What type of wave does not require a medium?
Definition
 electromagnetic
Term
 In a transverse wave, how do the particles move?
Definition
 at right angles to the direction of the wave; up and down
Term
 What is an example of a longitudinal wave and how do particles move in them?
Definition
 sound;parallel to the direction of the wave
Term
 What a compression? rarefaction? what kind of wave do you find them in?
Definition
 compression is when particles in the wave are closest together; rarefaction is when particles is the wave are far apart
Term
 energy's relationship to amplitude
Definition
 energy is proportional to amplitude squared
Term
 What determines the speed of the wave?
Definition
 the medium
Term
 What is reflection?
Definition
 the boucning back of a wave as it gets to the end of medium
Term
 What three things happen when a wave moves from one medium into a denser medium?
Definition
 out of phase reflection; reduction in amplitude (because of energy loss); speed change (slower in denser material)
Term
 What can change when a wave diffracts?
Definition
 direction
Term
 What never changes when a wave refracts?
Definition
 frequency
Term
 The bigger the wavelength, the better____.
Definition
 diffraction
Term
 What is the principle of superposition?
Definition
 one wave is on top of another wave and form a new wave for a moment
Term
 When does a standing wave occur?
Definition
 when 2 waves of the same frequency and amplitude approach each other
Term
 What is a node?
Definition
 the points in the medium that are displaced; where crests/troughs meet
Term
 What is anti-node?
Definition
 the parts that are moving; where crests meet
Term
 Simple harmonic motion is always in the direction of the ____.
Definition
 equlibrium position
Term
 What is an example of a simple harmonic oscillator?
Definition
 mass vibrating at end of string
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