1. AP Physics 1 Review Session 4
Oscillations, Waves, & Electricity

2. Simple Harmonic Motion
Objects oscillate with a constant period/frequency
As the position from the equilibrium position increases, the restoration force increases
Energy constantly changes from potential to kinetic

3. Key Terms

4. Graphs of SHM

5. Equation of SHM

6. The simple pendulum
A pendulum is a vibrating system in which the motion is very apparent.
Consider a simplified model of a pendulum system that has a compact object (a bob) at the end of a comparatively long and massless string and that undergoes small-amplitude vibrations.
This idealized system is called a simple pendulum.
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7. The simple pendulum Two objects interact with the bob of the pendulum.
The string S exerts a force that is always perpendicular to the path of the bob.
Earth exerts a downward gravitational force.
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8. Examples of SHM
Pendulums
Mass-Spring Systems

9. Mechanical Waves
Waves that travel through matter
Wave Speed

10. Two kinds of waves
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11. Superposition principle for waves
The process in which two or more waves of the same frequency overlap is called interference.
Places where the waves add to create a larger disturbance are called locations of constructive interference.
Places where the waves add to produce a smaller disturbance are called locations of destructive interference.
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12. Loudness and intensity
Loudness is determined primarily by the amplitude of the sound wave: the larger the amplitude, the louder the sound.
Equal-amplitude sound waves of different frequencies will not have the same perceived loudness to humans.
To measure the loudness of a sound, we measure the intensity: the energy per unit area per unit time interval.
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13. Pitch, frequency, and complex sounds
Pitch is the perception of the frequency of a sound.
Tuning forks of different sizes produce sounds of approximately the same intensity, but we hear each as having a different pitch.
The shorter the length of the tuning fork, the higher the frequency and the higher the pitch.
Like loudness, pitch is not a physical quantity but rather a subjective impression.
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14. Fundamental and harmonics
The lowest frequency of a complex wave is called the fundamental.
Higher-frequency components that are whole-number multiples of the fundamental are called harmonics.
We usually identify the pitch as the fundamental frequency.
The complexity of the waveform (the number of harmonics) contributes to the quality of the sound we associate with specific instruments.
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15. Beat and beat frequencies
Two sound sources of similar (but not the same) frequency are equidistant from a microphone that records the air pressure variations due to the two sound sources as a function of time.
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16. Beat and beat frequencies
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17. Standing waves on strings
You shake the end of a rope that is attached to a fixed support.
At specific frequencies, you notice that the rope has large-amplitude sine-shaped vibrations that appear not to be traveling.
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18. Standing waves on a string
The lowest-frequency vibration of the rope is one up-and-down shake per time interval:
This frequency is called the fundamental frequency.
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19. Standing wave vibration frequencies in open-open pipes
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20. Standing wave vibration frequencies in open-closed pipes
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21. The Doppler effect: Putting it all together
When you hear the sound from a horn of a passing car, its pitch is noticeably higher than normal as it approaches, but noticeably lower than normal as it moves away.
This phenomenon is an example of the Doppler effect.
The Doppler effect occurs when a source of sound and an observer move with respect to each other and/or with respect to the medium in which the sound travels.
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22. Doppler effect for the source moving relative to the medium
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23. Electrical Force Directly related to product of charge
Inversely related to the square of the distance between them

24. Contemporary model for electric charge
Two objects start as neutral—the total electric charge of each is zero.
During rubbing, one object gains electrons and becomes negatively charged.
The other object loses an equal number of electrons and with this deficiency of electrons becomes positively charged.
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25. Current
Moving charges
Measured in Amperes

26. Electrical Resistance

27. Ohm’s Law

28. Joule’s Law

29. Kirchhoff’s Rules

30. Series resistance
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31. Parallel resistance
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