Harmonic Waves: Understanding Sinusoidal Behavior, Wave Speed, and Wave Power, Slides of Physics

Download Harmonic Waves: Understanding Sinusoidal Behavior, Wave Speed, and Wave Power and more Slides Physics in PDF only on Docsity! Harmonic Waves Docsity.com Sinusoidal Behavior  An harmonically oscillating point is described by a sine wave. • y = A cos t  An object can take a sinusoidal shape in space. • y = A cos kx 1 period 1 wavelength y y t x Docsity.com Seasick  While boating on the ocean you see wave crests 14 m apart and 3.6 m deep. It takes 1.5 s for a float to rise from trough to crest.  What is the wave speed?  The time from trough to crest is half a period: T = 3.0 s.  The wavelength is  = 14 m.  The speed can be found directly: v = /T = 4.7 m/s. Docsity.com Wave Power  Wave energy is proportional to amplitude squared. • E = ½ mv2 = ½ L(A)2  Power is the time rate of change of energy. • Proportional to the speed • Proportional to the amplitude squared vAP tLAP tEP 22 2 1 2 2 1 )/()( /      Docsity.com Intensity  Intensity of a wave is the rate energy is carried across a surface area.  This is true for linear and other waves.  For a spherical wave, the intensity I = P/A = P/4r2 Docsity.com