Waves 41 Oscillations Introduction All motion is either periodic or nonperiodic In periodic motion an object repeats its pattern of motion at a fixed interval of time it is regular and repeated Wave motion is also periodic and there are many similarities between oscillations and waves ID: 728934
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Slide1
Topic 4: Oscillations & Waves
4.1 OscillationsSlide2
Introduction
All motion is either periodic or non-periodic. In
periodic
motion an object repeats its pattern of motion at a fixed interval of time: it is regular and repeated. Wave motion is also periodic and there are many similarities between oscillations and waves; in this topic we will consider the common features but also see that there are differences.Slide3
Objectives & Understandings
SWBAT
Qualitatively describe the energy changes taking place during one cycle of an oscillation
Sketch & interpret graphs of simple harmonic motion examplesUnderstand what is meant by simple harmonic motion (SHM) & its conditionsUnderstand and define the terms time period, frequency, amplitude, displacement, and phase difference.Slide4
Some Key V
ocabulary
Wave -
a disturbance that transfers
energy (not matter) through a medium from one location to another
location Medium - a substance or material that carries the wave
Equilibrium position – the rest position; zero displacement
Amplitude – A - maximum value for the displacement
Frequency – f - number of oscillations per second
Period – T - time required for one complete oscillation
Angular frequency – ω - the magnitude of the vector quantity angular velocity (radians/second)
Slide5
Oscillations
Isochronous oscillations – (Pronunciation: ī-ˈ
sä-krə-nəs
)
The
Latin breakdown:
Iso
(same)
chronos
(time
)repeat in the same time periodDescribing periodic motionWavelength – λ - distance from crest to crest or trough to trough.Also all the other vocabulary that we just discussed…Slide6
Practice
In the diagram above, which letter refers to a wavelength?
In
the diagram above, which letter refers
the amplitude?Slide7
More Practice
What is the amplitude of each wave on the graph below? What is the wavelength?Slide8
Simple Harmonic Motion
Conditions – the magnitude of the acceleration is proportional to the displacement of the object from a fixed point
and
the direction is always towards that fixed point.
Spring restoring force: F=-
kx
Watch this video to view the x, v, and a graphs for an object undergoing simple harmonic motion
Watch this video to view the conservation of energy in simple harmonic motion
Slide9
Graphs: Simple Harmonic Motion
Displacement, velocity & acceleration time graphs
Acceleration-displacement graphSlide10
Check for Understanding
During SHM, where would the object have the greatest displacement?
During SHM, where would the object have the greatest
velocity?During SHM, where would the object have the greatest acceleration?Slide11
Energy Changes in SHM
Total energy remains constant (conserved)
Potential energy is a minimum at equilibrium & maximum at maximum displacement
Kinetic energy is a maximum at equilibrium & minimum at maximum displacementSlide12
Phase & phase difference
Phase difference
- φ - the measure of how "in step" different particles are. If they are moving together they are said to be in phase. If not they are said to be out of phase.Slide13
Phase Difference continued
Example: the phase difference between the displacement and velocity graphs is T/4 or 90° or
π
/2 radians.Period T = 360° = 2π radiansT/2 = 180° =
π radiansT/4 = 90° = π/2
radiansWhat is the phase difference between displacement and acceleration?Slide14
Elaborate
Create vocabulary tabs for the 10 “new” vocabulary terms listed below. Include a definition & picture. If applicable, include equations, units & symbols. Use at least 4 colors
. Place the word on the front.
Wave
Medium
Equilibrium
Position
Simple Harmonic Motion
Crest/Trough
Amplitude
Frequency PeriodWavelength Phase differenceSlide15
Elaborate
Try this problem set
Whiteboard one problem & present the solution to the class.