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This article provides an overview of waves, including their types, characteristics, and velocity. It discusses transverse, longitudinal, and torsional waves, as well as the properties of wave trains. Examples and visual resources are included to enhance understanding.
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Waves PhysicsMrs. Coyle Coyle, Greece 2005, North Aegean Sea
Waves and their characteristics • Velocity of a wave • Types of waves
Oscillation • Object moves back and forth about an equilibrium position.
Pulse: A single disturbance travelling through a medium. http://www.dacc.edu/~qchen/P102/labs/LAB5.HTM
Wave Train (Travelling Wave or simply wave): • A series of pulses at regular intervals. http://micromachine.stanford.edu/~hopcroft/Research/resonator_images/sin_mov1.gif
Wave on a String • (Applet) http://phet.colorado.edu/sims/wave-on-a-string/wave-on-a-string_en.html
Speed of a Wave, v v= d/t v = l/T v =lf
Types of Waves • Transverse • Longitudinal
Transverse The particles vibrate perpendicular to the direction of the wave's propagation (ex: waves along a string, electromagnetic waves).
Example: S Earthquake Wave http://web.ics.purdue.edu/~braile/edumod/waves/Swave_files/image001.gif
Longitudinal Waves • The particle displacement is parallel to the direction of wave propagation (ex: sound)
Torsional Waves • Video link on Web : Collapse of Takoma Narrows Bridge, Washington State, 1940 • http://www.youtube.com/watch?v=shX4Q0QV8VI
Elliptical Waves Result when longitudinal and transverse waves are superpositioned. (ex: surface water waves)
Ocean Wave http://www.pa.uky.edu/~crawford/phy361_sp10/home.html
Note • Waves transfer of energy from one point to another. • Waves do not transfer matter.
Types of Waves • MechanicalWaves • Electromagnetic Waves
Mechanical Waves require a medium. Examples: • Water waves( Tsunami) • Sound waves (v= 340 m/sec in air but varies for different media) • Earthquake waves
Electromagnetic Waves do not require a medium and can travel through the empty space (vacuum). Example: • Light from the sun travels through space and reaches us. Note: All EM waves have a speed through vacuum of 3 x 108 m/sec.
Problem 1 • What is the distance a sound wave in air traveled in 2 sec?Answer: 680m/s
Problem 2 • What is the frequency of a light wave of wave length 550x 10-9 m? • Answer: 5.5 x 10 14 Hz
Problem 3 • A SONAR (Sound Navigation and Ranging) sends a signal to the bottom of the ocean. The speed of sound in water is 1435 m/s. If the signal echo returned in 0.4 sec, how deep was the water? • Answer: 287m