Physics Test Ch. 1&2

Unrelated

two items that are not associated with one another (cactus is unrelated to a toaster)

Related/proportional

two things that go together, but the reason is unclear (cars are related to gasoline)

Directly related/proportional

when the qunitity of one item increases, the other increases at the same rate: the amount of gasoline is directly proportional to the distance a car can travel

Inversely related/proportional

when the quanitity of one ite increases, the other decreases at the same rate (the more you shop, the less money you have)

reciprocals

a pair of numbers that, when multiplies together, equal 1. When one number increases, the other number will decrease (1 and 1/10)

Name the three units of measure

length, area, volume

length

distance: cm, ft, miles

Area

cm², ft², square centimeters, square foot

volume

cm³, ft³, cubic centimers/foot

increase by a factor of x

multiply by x

decrease by a factor of x

divide by x

raising numbers to a negative reciprocal

a^-n = 1/a^n

ex: 5^-2 = 1/25

billions and billionths

giga and nano, G&n (same for every other unit)

time

seconds, nanoseconds

power

watts, pascals (Pa)

work

joule

acoustic impendence

rayl

waves carry ___ from one location to another

energy

Sound is a ___ and a ____ wave

mechanical, longitudinal

what do mechanical waves need in order to propogate ?

a medium

which way do particles travel in a longitudinal (sound) wave?

travel in a straight line

compression

molecules squeezed together, high pressure and density, above the baseline

rarefaction

molecules stratched apart, low pressure and density, below the baseline

Biologic effects

the effect the sound wave has on the tissue through which it passes

Acoustiv propogation properties

effect of the medium upon the sound wave

Acoustic variables

changes that occur within a medium as a result of sound traveling through it allowing us to determine between sound waves and other types of waves

When an acoustic variable _______, a ____ is present

changes rythmically in time (cyclical), sound wave

Name the 4 acoustic variables

pressure, density, distance, temperature

Pressure

concentration of force in an area, Pascals (Pa)

Density

concentration of a mass in a volume (mass/volume)

kg/cm³

Distance

measure of particle motion (move parallel to a wave)

cm, mm, feet, mile

Temperature

heat is produced by any mechanical system, some energy is lost to heat within the medium

celcius, fahrenheit

When is a wave NOT a sound wave ?

if there are other variables in rythmic oscillation

Transverse wave

particles move in a perpendicular direction to the wave (NOT a sound wave)

Acoustic parameters

describe and measure the waves features

What is the difference between acoustic variables and acoustic parameters?

Acoustic variables define what a sound wave is, while acoustic parameters describe the features of that sound wave

Name the seven acoustic parameters

period, frequency, amplitude, power, intensity, wavelength, propogation speed

In-phase wave

pair of waves peaks and troughs occur at the same time and same location

Out-of-phase waves

peaks and troughs occur at different times (out of step)

Interference

when two waves combine to form a single wave as a result of multiple beams arriving at the same location at exactly the same time. Waves will lose their individual characteristics

Constuctive interference

interference of two in-phase waves that, when combined, result in a bigger wave

Destructive interference

interference of two out-of-phase waves that, when combined, result in a smaller wave