Motion in One Dimension
Motion
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defined as the change in position for a certain time interval
can answer the question: “How far did the object travel?”
Distance
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length of the entire path traveled
magnitude ONLY (numerical value)
Scalar quantity
independent variable in a distance-time graph
Displacement
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distance between the starting and ending point
magnitude with DIRECTION
vector quantity
Speed
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change in distance within a given time interval
measure of how fast an object is
formula: Speed = Distance/Time
time is the dependent variable in a distance-time graph
Uniform Motion/Constant Speed
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the speed of the object is not changing
Instantaneous Speed
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the speed of the object at a given instant of time
Speedometer
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a device/tool used to measure the instantaneous speed of a vehicle
FORMULA TRIANGLE:
D
S
T
Analyzing Motion
Ticker Timer
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provides a dot diagram for an object’s motion
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if the distance between the dots is near but equal, then it is at a slow, constant speed
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if the distance between the dots is far but equal, then it is at a fast, constant speed
Assume the object is moving to the right, and the ticker timer is on the left.
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if the distance between the dots gets longer from start until the end, then it is accelerating
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if the distance between the dots gets shorter from start until the end, then it is decelerating
Motion Graphs
ACCELERATION
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change in velocity
measured in m/s/s or m/s²
formula: Δv/ Δt OR vf-vi/tf-ti
Δ (delta) = change
vf = final velocity
vi – initial velocity
tf – final time
ti – initial time
Acceleration due to Gravity
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Value: 9.8m/s²
symbol: g
acceleration of an object caused by the force of gravitation (neglecting other forces)
FREE FALL – any motion of a body where gravity is the only acceleration acting upon it
FORMULA TRIANGLE
v
a
t
Waves
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disturbances that carry energy through matter or space
Vibration
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back and forth
up-down movement
Medium
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any form of matter through which waves can travel
Mechanical Waves
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requires medium to travels
Electromagnetic Waves
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does not require medium to travel
Types of Waves
Transverse Waves
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particles move perpendicular to the wave’s motion
Longitudinal Waves
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particles move parallel to the wave’s motion
Parts of Waves (Transverse)
a.
b.
c.
d.
e.
Crest – the highest point of a wave
Trough – the lowest point of the wave
Middle line – resting point
Amplitude – distance from the resting point to the crest
Wavelength – crest to crest/trough to trough
Parts of Waves (Longitudinal)
a.
b.
c.
d.
Compression – compressed part of the wave
Rarefaction – un-compressed part of the wave
Amplitude – how compressed its medium is
Wavelength – compression to compression/rarefaction to rarefaction
Frequency
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number of waves that pass a given point in a certain time
Hertz = 1 wave per second
WAVE SPEED
Formula:
Speed = frequency x wavelength
OR
Speed = fλ
FORMULA TRIANGLE
v
f
λ
Sound
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longitudinal line
requires medium
slowest wave speed = gases
fast wave speed = liquids
fastest wave speed = solids
Properties of Sound
Pitch
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highness or loudness of sound
Frequency
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number of waves that pass a given point in a certain time
Loudness
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human perception of sound intensity
measured in decibels (dB)
a human ear can hear 20-20,000 dB
Quality
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describes the difference between sounds
Timbre
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blending sounds in different frequencies
Fundamental Tones
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lowest natural frequency of an object
Overtone
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highest natural frequency
Light
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electromagnetic wave
travels in a straight path
Transparent
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objects have all light pass through
Translucent
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light still passes through but it is distorted already
Opaque
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objects has little or no light pass through
Electromagnetic Spectrum
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inversely proportional (wavelength decreases, frequency increases and vice versa)
Behavior of Light
Speed of Light
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depends on the density of an object
vacuum = fastest
diamond = slowest
Black vs White Light
Light Sources
Good luck!