Let’s Review: Let’s Review Douglas and the Wave http://www.youtube.com/watch?v=a1YlqVojkuU


Wave Comparisons(See Notes): Wave Comparisons (See Notes) Water Waves Sound Waves Light Waves Waves Medium Wave Speed What if you go faster? Human Perception


Speed of Waves: Speed of Waves Wave speed depends on the medium Example: Speed of sound In dry air at 21°C, sound speed = 344 m/s In fresh water at 25°C, sound speed ≈ 1500 m/s


Shock Wave: Shock Wave http://observe.phy.sfasu.edu/courses/phy101/lectures101/


Subsonic: - slower than the speed of sound Subsonic Supersonic - faster than the speed of sound Mach Number = speed of sound speed of object


Transverse Waves: Transverse Waves side to side vibration in a direction perpendicular to the wave's motion Examples: water waves waves on a rope string musical instruments


Longitudinal Waves: Longitudinal Waves back and forth vibration in a direction parallel to the wave's motion Examples: slinky waves sounds waves (vortex box)


Slide8: http://www.kettering.edu/~drussell/Demos/waves/wavemotion.html


INTERFERENCE: INTERFERENCE More than one wave can exist at the same time in the same space. When they exist at the same time and space, their displacements are added. Constructive or destructive interference results when waves add. http://physics.bu.edu/~duffy/semester1/c21_interference.html


Standing Waves: Standing Waves Two waves with the same frequency, wavelength, and amplitude will interfere and produce standing waves. Standing wave – stationary vibrating pattern. Ruben’s Tube Tie a rope to a stationary object and shake it. With the right frequency, the incident wave (outgoing) will be in phase with the reflected wave (incoming) and produce a standing wave http://www.ngsir.netfirms.com/englishhtm/StatWave.htm


DOPPLER EFFECT: DOPPLER EFFECT the change in wavelength due to motion of the source "Wheeeeeeeeeeee…….Oooooooooooooo” Examples: moving cars and trains Draw Doppler Picture Java Doppler Effect


Slide12: http://www.kettering.edu/~drussell/Demos/doppler/doppler.html


Slide13: Quick Questions…. Web Page


Example Question: Example Question A train whistle at rest has a frequency of 3000 Hertz. If you are standing still and observe the frequency to be 3010 Hertz, then you can conclude that... a) the train is moving away from you. b) the train is moving toward you c) the sound from the whistle has echoed d) not enough information is given *


Example Question: Example Question Changing which of the following affects the period of a pendulum? a) mass b) amplitude c) length d) angle *


Example Question: Example Question Dipping a finger in water faster and faster causes the wavelength of the spreading waves to a) increase b) decrease c) stay the same d) not enough information is given *


Example Question: Example Question The distance from trough to trough on a periodic wave is called its... a) frequency. b) period. c) wavelength. d) amplitude. *


Chapter 19 – Vibrations and Waves: Chapter 19 – Vibrations and Waves End of Part 2