Section 1
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beats are produced when
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Last updated
6 years ago
Date created
Mar 1, 2020
Cards (62)
Section 1
(50 cards)
beats are produced when
two waves have different frequencies
if you half the length of a string the frequency
doubles
/\ f
width at half the amp
find p
mass / length
sec to ms
1 sec = 1000 ms
damping time is
the time it takes for the amplitude to decrease to half of its value
cm to m
x .01
how does the pitch you hear from the pipe as it gets colder compare to the pitch you hear when the pipe is warm
the pitch would get lower when it is colder - colder temp = slower speed of sound
touch a string at (point)
modes where have a node at (point) will survive -induce node at that (point)
if you increase damping then the damping time
decreases
harmonic motion
what happens to the frequency of a 500 Hz piano string if its diameter is doubled with the material kept the same?
if you double the diameter then you halve the frequency
period
time it takes for one oscillation to occur
if you pluck a string at 1/3 the distance
1st, 2nd, 4th, 5th, 7th non multiples of 3
damping can be caused by
friction
force depends on length - keeping the tension the same
which mode requires more effort to sustain the oscillation: higher modes or the fundamental mode?
higher modes
You have a string that vibrates with a fundamental frequency of 600 Hz. If the tension was reduced to half of its former value, what is the new fundamental frequency?
600/ sqrt 2 =
node
a point at which lines or pathways intersect or branch; a central or connecting point
what happens to the pitch when the loudness is increased
pitch stays the same
if you decrease damping time the frequency width
increases
waves
periodic repetitive motion (motion that repeats)
how are pipes compared to strings
pipes are similar to strings in the fact that they both go down in frequency -velocity of a string depends on thickness while pipe depends on temp
hz to kilohertz
x .001
closed pipe
f = V/4L
how do the frequencies change when you make a pipe longer
the frequency goes lower
are the ends of pipe nodes or antinodes?
nodes h
A mass on a spring oscillates with a certain frequency f. What is the oscillation frequency if the spring is replaced with one that is four times weaker?
new oscillation frequency is half as large
what happens to pitch when frequency is increased?
pitch will increase
diameter affects freq of string and not pipe
if you pluck string at 1/5th distance
1,2,3,4,6,7,8,9,11 all non multiples of 5
antinode
point of maximum displacement or amplitude
frequency and period do not depend on amplitude
Circle the correct answers in the following sentence: Standing waves are the result of superposition of two sinusoidal waves of the same/different frequency and the same/different amplitude, traveling in the same/opposite directions.
same - same - opposite
What happens to the frequency of a piano string if you double the mass, keeping the same length and the same tension?
It goes down by a factor of sqrt 2 = 1.414.
if the force increases then displacement
increases
plucking a string at (point)
all modes that have a node at that (point) will disappear
if /\f increases the the damping time(T)
decreases
units for F=kx
F = force k = spring constant x = displacement
formula for period and frequency
f=1/T
pressure and relation to closed pipes
- node pressure at open end - antinode pressure at close end
What happens to the frequency of a 600 Hz piano string if you changed the tension from 200N to 50N?
600 hz / f2 = sqrt 200 / sqrt 50
frequency
how many oscillations occur per second
are resonant frequency and natural frequency the same thing?
yes - resonant frequencys always resonates at the natural frequ
what happens to the frequency you hear when you double the diameter of the pipe
it gets slightly lower because the diameter changes the effective length of the pipe to be slightly longer
if a wave has more friction then
- it will have greater energy loss - damping time will decrease - /\f will increase - lower and wider curve
1 gram =
.001 kg
if you pluck a string at the center which modes will be excited?
1st, 3rd, 5th, 7th.... all odd modes
open pipe equation
f= v/2L
equation to find phase change
phase/360 = /\t/T
Section 2
(12 cards)