Introduction to Waves - 8/25

what is oscillation?

a motion in which an object shows regular fluctuation in value, position, and/or state about a mean value

this graphic is an example of…

oscillation

label the diagram

1: amplitude

2: crest

3: wavelength

4: amplitude of wave

5: time

6: trough

7: 1 cycle

what is period (T)? what is its unit?

the amount of time to complete 1 cycle. unit: seconds

what is frequency (f)? what is its unit?

number of cycles/oscillations per second. unit: Hz

what is the relationship between f and T?

f = 1/T

T = 1/f

f and t have an inverse relationship. as f increases, T decreases

if there is 1 cycle in 1 second, how many hertz?

1 Hz

is there are 2 cycles in 1 second, how many hertz?

2 Hz

if there are 10 cycles in 1 second, how many hertz?

10 Hz

if the frequency (f) is 2 Hz, what is the period (T)?

0.5 s

if the frequency (f) is 10 Hz, what is the period (T)?

0.1 s

if the period (T) is 2 s, what is the frequency (f)?

0.5 Hz

if the period (T) is 0.25 s, what is the frequency (f)?

4 Hz

as frequency (f) increases, period (T) ______

decreases

as period (T) increases, frequency (f) _____

decreases

what is phase?

a sound wave’s position within its cycle. measured in degrees

label the phase (degrees)

A: 0, 360 degrees

B: 90 degrees

C: 180 degrees

D : 270 degrees

what is amplitude (A)?

maximum displacement of a wave measure from its equilibrium position

what are the 2 ways to measure amplitude? define them

peak to peak: measure from positive to negative peak

reference line to peak: measure from baseline to peak

measure both peak-to-peak amplitude and baseline-to-peak amplitude

peak to peak A: 4

baseline to peak A: 2

what is the frequency?

1 Hz

what is the frequency?

2 Hz

an object in simple harmonic motion completes 1000 oscillations in a second. what is its frequency?

1000 Hz

what is wavelength (λ) ? what is its unit?

the distance from one peak to the next adjacent peak. unit: meter

what is the relationship between wavelength (λ) and frequency (f)?

as wavelength increases, frequency decreases. as frequency increases, wavelength decreases.

f = 1/λ

λ = 1/f

inverse relationship!

shorter wavelength = ______ frequency

higher

longer wavelength = _____ frequency

lower

frequency is the physical correlate of ____

pitch

amplitude is the physical correlate to ____

loudess

in a pendulum, what determines the frequency?

the length of the pendulum

what is the equation for period (T) of a pendulum?

T=2π√L/g

where L is length and g is gravitational force

what 3 factors determine the frequency of a guitar string?

mass, length, and tension

what is a mechanical wave?

a disturbance traveling in an elastic medium like air, glass, metal

what are the 2 kinds of mechanical waves? define them

transverse wave: particles move perpendicular to the direction in which the wave travels = string waves

longitudinal waves: particles of the medium move parallel to the direction in which the wave travels, characterized by compressions and rarefactions = sound waves

this graphic is a _____ wave. does it represent a sound or string wave?

transverse wave, represents a string wave

this graphic is a _____ wave. does it represent a sound or string wave?

longitudinal wave. represents a sound wave

what is compression?

a region where particles of a medium are crowded together

what is rarefaction?

a region where particles of a medium are more spread apart

the areas in the red circles represent _____, while the ares in the blue squares represent ____

compression, rarefaction

a 100 Hz sine wave has a [longer, shorter, equal] wavelength than a 1000 Hz sine wave

longer

what is the frequency of a sine wave with a 10 second period?

0.1 Hz

f and λ have a/n [direct/inverse] relationship

inverse

f and T have a/n [direct/inverse] relationship

inverse

T and λ have a/n [direct/inverse] relationship

direct. as T increases, so does λ