Oscillation and Waves Flashcards
Periodic or harmonic motion
Any motion that regularly repeats
Period
The time it takes an object to move through one full cycle of motion
Denoted by T and is measured in seconds
Frequency
The number of cycles that occur in one second
Denoted by f and measured in Hertz (Hz)
Period and Frequency
T=1/f and f=1/T
Spring constant
Tells us how strong the spring is
The greater the value of k, the stiffer (and stronger) the spring
Units = newton/meter
Direction of the spring force is always directed opposite to its displacement from equilibrium
Amplitude
The maximum displacement of the block from equilibrium
Denoted by A
This number tells us how far to the left and right of equilibrium the block will travel
The kinematics of SHM
Neither frequency nor period are dependent on amplitude
Simple pendulum
If the connecting rod or string between the suspension point and the object at the end of a pendulum has negligible mass, and if there is no friction at the suspension point during oscillation
Mechanical waves
A series of disturbances (oscillations) within a medium that transfers energy from one place to another
Mechanical waves cannot exist without a medium
Transverse wave
The wave travels in a direction thats perpendicular to the direction in which the medium is vibrating
Frequency (waves)
The number of pulses that pass a given point per unit itme
Period (waves)
The time it takes between pulses
Wavelength
The distance from one crest to the next
One wave cycle
Amplitude (eaves)
The maximum displacement from equilibrium that any point in the medium makes as the wave goes by
Wave equation
v=lambda(f)
Changing f doesnt change v, it changes lambda
Wave rule 1
The speed of a wave is determined by the type of wave and the characteristics of the medium, not by the frequency
Different waves in one medium
Wave rule 2
When a wave passes into another medium, its speed changes, but its frequency does not
Single wave in different media
Interference
When two or more waves are superimposed on each other, they will combine to form a single resultant wave
The waves can be of different wavelenghts
In phase
When crest meets crest and trough meets trough
Their amplitudes with add and the waves interfere constructively
The path difference = n(lambda) and, (n=0,1,2,…), the waves will be in phase and will therefore constructively interfere
Out of phase
The crest of one wave coincides with the trough of the other
Their amplitudes subtract and the waves interfere destructively
The path difference = (n=1/2)(lamda), the waves will be out of phase and will therefore destructively interfere
nodes
Points of no displacement
Antinodes
Halfway between any two consecutive nodes are points where the amplitude is maximized