Lesson 6 Flashcards
How are Oscillations related to Waves?
Oscillations provide the basis for waves. Waves cannot exist without oscillations.
What is Houke’s Law
~ Fs = -kx
~ ΣFx = max
~ -kx = max
~ ax = (-k/m)x
~ a = dv/dt = d2x/dt
Define simple harmonic motion
~ ax = (-k/m)x therefor d2x/dt = -k/mx —–> d2x/dt = -ω2x
How to Remember sine and cosine
^ Sin
| Cos
| -Sin
| -Cos
~ Going up is integrating going down is derivation
What is the amplitude of a wave
The maximum value of position in either the positive or negative direction.
What is the SI Unit for amplitude?
Meters
What is the Angular Frequency
~ ω = sqrt k/m
~ SI units : radians/sec
~ (ωt + Φ) Phase of Motion
~ Φ Phase Constant
~ Initial angle at x=a, Φ = 0
What is a period?
~ T = 2π/ω
~ ω = angular frequency
~ The time required for a particle to go through one full cycle of motion
~ SI Units: Seconds
What is frequency?
~ The rate at which a vibration occurs that constitutes a wave, either in a material (as in sound waves), or in an electromagnetic field (as in radio waves and light), usually measured per second.
~ f = frequency = f = 1/T –>1/secs or sec-1
~ Hz or cycles/sec
Define Mechanical waves
~ A mechanical wave is a vibration that moves through matter and transfers energy.
How does wave pulse travel
Perpendicular to the force
How do transverse waves travel?
Up and Down
How do Longitudinal waves travel?
Left and Right
What are crest and troughs/Rarefactions and compressions?
~ Crest - High points in a wave
~ Troughs - Low points in a wave
~ Rarefactions - Spread out sections of a wave
~ Compressions - More compressed sections of a wave
What is a wave function?
~ y(x,t) = f(x-vt) For a wave traveling in the positive x direction. Solve for the y position at some point in time
~ If sign is negative, travelling in positive direction
~ y(x,t) = f(x+vt) For a wave travelling in the negative direction
What is a wavelength
~ λ = wavelength
~ SI Units: Meters
