Waves and Sound Flashcards
(27 cards)
What is periodic motion? What is the motion called?
The pattern of motion repeating itself at regular intervals. Cycle or Vibration.
What are the 2 types of vibrations?
Transverse which travels perpendicular (up and down) along the medium. Longitudinal which travels parallel along the medium
What is the Rest Position/ Equilibrium Position?
The place where the object will naturally not move.
What is Amplitude?
The maximum distance of the vibrating object from it’s rest position.
Crest vs Trough
The amplitude above (crest) and below (trough) the rest position.
What is frequency? What is it measured in?
Frequency is the number of cycles that occur in a unit of time. Measured in Hertz (Hz).
1Hz = 1s^-1
Where have you seen vibrations in the real world?
swings, walking, tides, yo-yo, humming bird’s wings, pendulum
What is a wave?
The transfer of energy (by a series of vibrations) in the form of a disturbance, usually through a material medium.
What are the 2 types of waves?
Transverse waves - the motion of the medium is at right angles to the direction of the wave travel
Longitudinal waves - the motion of the medium is in the same direction as the wave travel
What is another name for a transverse wave? A longitudinal wave?
Transverse - s or shear wave
Longitudinal - p or pressure wave
What is a wavelength? What is it’s symbol?
The distance between 2 adjacent points. Lambda (upside down y shape)
What is a natural frequency?
The frequency an object will vibrate at if no external force is applied.
What equations work for both waves and vibrations?
T(period) = Δt/N Period and frequency are transverse of each other f = N/Δt f = 1/T
In phase
2 or more waves are at the same point and moving in the same direction
Opposite wave
2 or more waves are always moving in the opposite direction
Out of phase
2 or more waves are not at the same point and/or moving in the same direction
Define resonance
The transfer of energy from one vibrating object to another object having the same natural frequency.
The Doppler Effect
The change in frequency of the wave emitted by a fast moving object as it passes by you. Principal used for radar trap.
What is Diffraction?
The bending of a wave as it nears an object. Waves pass through and opening larger than the wave length with little diffraction.
Why can we hear but not see around corners?
Sound is able to diffract around corners and not sound because it has a bigger wave length than light.
What happens when a wave (such as a
in a spring), hits a more dense medium? A less dense medium?
The reflected wave comes back inverted. The reflected wave comes back in phase.
Define: Normal. angle of incidence, angle of reflection, propagation rays.
Normal: right angle to the barrier
Angle of Incidence: Angle between incident ray and normal
Angle of Reflection: Angle between reflective ray and normal
Propagation Ray: Ray that is right angle to the wave
When does Constructive Interference occur?
When 2 waves push the medium in the same direction - the wave becomes bigger than either of the individuals. This can result in a super crest or super trough.
When does Destructive Interference occur?
When 2 waves push the medium in opposite directions - the wave becomes smaller then either of the individual waves.
