14.1 Mechanical Oscillations, Wave Types and Graphs Flashcards
What is a wave?
Waves are vibrations that transfer energy from place to place without matter (solid, liquid or gas) being transferred.
What is a progressive wave?
One that carries energy away to another place without matter
How can we tell a wave carries energy?
- EM waves makes things heat up
- X rays and gamma rays ionise materials
- Loud sounds make things vibrate
- Wave power can generate electricity
What is a mechanical wave?
One that requires a medium for transmission of energy and are generated by vibrating sources. (energy from vibrations is transmitted using vibrations of particles of the medium)
What is the easiest way to demonstrate waves?
Using a slinky spring
What is the relationship between frequency and time period?
f = 1/t
What is a transverse wave?
wave consisting of vibrations (usually of particles) perpendicular to the direction of travel of the wave
How do we remember a transverse wave?
TRAN90
Examples of transverse waves?
- EM waves
- ripples on water
- stringed instrument vibrations
- s waves (secondary seismic)
What is a longitudinal wave?
one where vibrations are parallel to the direction of travel of the wave
What does this wave consist of that a transverse one doesn’t?
Sections of compressions and rarefactions of medium.
Compression is where oscillations happen close to each other
Rarefaction is where oscillations(and hence particles) are more sparsely located
Examples of longitudinal waves
- sound waves
- p waves (primary seismic)
What do compressions and rarefactions create?
Areas of high and low pressures
What is the displacement?
how far a point has moved from the equilibrium position
what is the amplitude?
Maximum displacement from the mean (equilibrium) position in meters
What is the wavelength?
the length of one whole wave cycle (crest to crest) or (trough to trough)
What is the period?
the time taken to complete 1 oscillation
What is the frequency?
the number of complete oscillations in 1 second (measured in hertz)
What is a phase?
measurement of position within a cycle that a particle occupies within a wave cycle
What is a phase difference?
the difference between one wave compared to another in terms of degrees or radians
What 2 types of graphs can be used to represent waves?
displacement time graphs
displacement distance graphs
What is a wave graph referred to as?
A waveform
What is often the shape of these graphs?
Sine graphs
What does it mean to be in phase?
In the same point of the wave cycle
What does it mean to be in antiphase?
Points which are half the cycle out of each other
What would a displacement distance/time graph look like for a longitudinal wave?
A sine wave, however displacement would represent movement to right/left instead of up or down
