Waves Flashcards
GOAT ACTIVITY
What is a mechanical wave?
it is a disturbance carrying energy through a physical medium and displacing particles.
What is a wavelength?
the distance between two wave crests or troughs;
the smallest repeat unit of a wave’s motion;
the distance between two points of equal phase
What is a wave number, its equation and its units?
it is the rate of change in phase w.r.t distance
k = 2pi/lambda
rad / m
What is a transverse wave?
A disturbance of in a medium causes the direction of motion to be perpendicular to the motion of the particles
What is a longitudinal wave?
when the particle displacement in the wave is parallel to the directional motion of the wave.
What are the two ways of viewing waves?
the displacement of all the particles in a wave at a given time
the displacement of a particle with respect to time
What is the difference between angular frequency and wave number?
angular frequency is the change in phase w.r.t time (displacement vs time) and wave number is the change in phase w.r.t distance (displacement vs distance)
What is phase velocity?
this is the velocity at which a wave propagates through a medium.
***don’t confuse this with particle velocity, it’s different.
What is particle (transverse) velocity?
The rate of change in distance for a particle in a wave.
What is phase velocity dependent on and independent from?
phase velocity is dependent on tension and mass per unit length (rho) and independent from amplitude and frequency.
when tension increases and or rho decreases then phase velocity increases. the opposite is also true.
If two strings are identical in everything except mass per unit length, which string would be faster?
The string with the lower mass per unit length
What are acoustic waves?
These are longitudinal waves that traverse through mediums due to the vibration of particles as it travels
What are the two ways of describing a wave?
The displacement field and pressure field
What two material properties are sound wave speed dependent on and how? Describe them.
The wave speed is proportional to the bulk modulus and inversely proportional to density. The bulk modulus is the change in pressure and volume on a solid body. Density is the mass per unit volume.
Does a wave have power? Why or why not?
It does. When waves travel through a medium, it disturbs the particles with the use of energy. And so power is the rate at which energy disturbs the material.
