Physics, Chapter 25
Terms
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- Vibration
- A wiggle in time.
- Wave
- A wiggle in space and time.
- Period
- The time of a back and forth swing or a simple period of time from the beginning of something to the end.
- Simple Harmonic Motion
- The back and forth vibratory motion of a swinging pendulum.
- Sine Curve
- Pectorial representation of a wave.
- Crest
- High point of a wave.
- Trough
- Low point of a wave.
- Amplitude
- The distance from the mid-point to the crest (or tough) of a wave.
- Wavelength
- The distance from the top of one crest to the top of the next one.
- Frequency
- How frequently a vibration occurs.
- Hertz
- Unit of frequency.
- What is the source of all waves?
- Something that vibrates.
- If the frequency is 2 Hz, how much time is needed to complete one vibration? 3 Hz?
- 1/2 second, 1/3 second.
- Sound
- Energy that travels to our ears in the form of one kind of wave.
- T/F - It is the disturbance that moves along the length of the string, not the parts of the string itself.
- True
- What determines the speed of a wave?
- The medium through which it moves.
- When is a wave a "transverse" wave?
- Whenever the motion of the medium is at right angles to the direction in which a wave travels.
- Examples of transverse waves?
- In the stretched strings of musical instruments and upon the surfaces of liquids. Electromagnetic radio waves and light are also examples.
- Longitudinal Wave
- The particles move along the direction of the wave rather than at right angles to it.
- Interference Pattern
- Wave effects may be increased, decreased, or neutralized.
- Consructive Interference
- The result of a wave is increased amplitude.
- Destructive Interference
- Cancellation
- T/F - Interference is a characteristic of all sound waves.
- False, it is a characteristic of all wave motion in general.
- Node
- The parts of a rope on a standing wave that remain stationary.
- Anti-Nodes
- The positions on a standing wave with the largest amplitudes are known as antinodes.
- T/F - Standing waves can be produced in transverse and sound waves.
- False, standing waves can be produced in transverse or longitudinal waves.
- Doppler Effect
- The change in frequency due to the motion of the source. The greater the speed of the source, the greater will be the Doppler effect.
- Blue Shift
- An increase in frequency, named so because of the fact that the increase is toward the high-frequency, or blue, end color spectrum.
- Red Shift
- A decrease in frequency.
- Supersonic
- Faster than sound.
- Shock Wave
- A shock wave is produced by overlapping spheres that form a cone.
- Sonic Boom
- When the conical shell of compressed air that sweeps behind a supersonic aircraft reaches listeners on the ground below, the sharp crack they hear is described as a sonic boom.