Waves

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Waves
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Simple Harmonic Motion

• The back and forth or periodic motion of an
  object
• Ex. Pendulum, swings, second hand of a clock

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Waves

• Disturbance that moves through space or through a
  medium (material)
• Transfer energy not matter from one place to
  another

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In which direction will segment x move as the
wave passes through?

• (1) down, only (2) up, only (3) down, then up,
  then down (4) up, then down, then up

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Importance of Waves

• There are two ways to transmit information/energy
  in our universe particle motion or wave motion
• Waves can be produced two ways
• Mechanical Waves- vibration of particles
• Sound, water waves (water drop)
• Electromagnetic Waves- changing strength in an
  electromagnetic field (no medium required)
• Light, ultraviolet, x-rays (EM wave)

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• Wave train-series of evenly timed disturbances

• Pulse- single disturbance

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Transverse Waves

• Motion of the medium is at right angles
  (perpendicular) to the direction which the wave
  travels
• Ex. Vibrating string of musical instrument,
  electromagnetic waves( radio waves, light waves)

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Longitudinal Waves

• Particles vibrate parallel to the direction of
  wave travel and energy source
• Ex. Sound

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Longitudinal Wave terms

• Compression- (similar to crests) particles
  close together (high density)
• Rarefactions (similar to troughs)- particles
  spread out or rarefied (low density)

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Wave Property Definition Symbol Unit Determined by
Amplitude Maximum distance from the rest position A m Source of wave amount of energy being carried
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Velocity
Wave Property Definition Symbol Unit Determined by
Velocity Speed of the wave distance wave travels in a unit of time v m/s The medium
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Frequency
Wave Property Definition Symbol Unit Affected by-
Frequency of vibrations that pass a point each second Cycles per second f Hz Determined by source not medium!
Ex. 10 cycles pass a fixed point in a wave train
in 5 seconds. What is the frequency of the wave?
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Period
Wave Property Definition Symbol Unit Affected by-
Period Time it takes for one complete vibration T s Determined by source of vibration not medium
Which wave has the longest period?
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Wavelength
Wave Property Definition Symbol Unit Affected by-
Wavelength Distance wave moves during one complete vibration ? m Velocity Frequency (Determined by medium)
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Wave Equation

• Wave speed frequency x wavelength
• Ex. What is the speed of a wave with a frequency
  of 10 Hz and a wavelength of 0.25 m?
• 2.5 m/s

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Frequency and Period

• Frequency cycles/sec
• Period sec/cycle