1. Important Terms Chapter 25 Set #1 March 24, 2014

2. Definitions Vibration: An oscillation, a repeating back and forth motion about an equilibrium. Wave: A “wiggle in space and time”. A disturbance that repeats regularly in space and time that is transmitted progressively from one place in a medium to the next with not actual transport of matter.

3. Definitions Period: The time required for a complete orbit. The time required for a pendulum to make one two and fro swing. In general, the time needed to complete one cycle. Simple harmonic motion: Periodic motion in which acceleration is proportional to the distance from an equilibrium position and is directed toward that position.

4. Definitions Sine curve: A curve that represents the crests (peaks) and troughs (valleys) of a wave as traced out by a swinging pendulum that drops a trail of sand over a moving conveyor belt. Also, the visual representation of Alternating Current (AC) also known as common electricity found in household electric outlets.

5. Definitions Crests (Peaks): One of the places in a wave where the wave is highest or the disturbance is the greatest. Troughs (Valleys): One of the places in a wave where the wave is lowest or the disturbance is the greatest in the opposite direction from the wave.

6. Definitions Amplitude: The distance from the midpoint to the maximum (Crest or peak) of a wave or equivalently, from the midpoint to the minimum (trough or valley). Re: Sine Wave, the distance from the midpoint to any point on the curve. There will be a positive AND negative amplitude associated with this wave.

7. Definitions Wavelength: The distance from the top of the crest (peak) of a wave to the top of the following crest, or equivalently, the distance between identical parts on the wave. Frequency: The number or events (cycles, vibrations, oscillations or any repeated event) per unit time measured in Hertz (or events per unit time) Hertz: The SI unit of frequency, One hertz (Hz) ids one vibration (cycle) per second.