Speed and Medium for a Wave

School blocks YouTube? Download the file below

| Onsite |

| Mythbusters |


F. Speed – the number of meters a single cycle travels per second


1.  V = fλ   



solve for f: 



f = v/λ






inverse relationship











2. Speed of wave depends on the medium


(slower in dense media)

[ Flash ]




Rutgers University




Speed Of a Mechanical Wave

[ HTML5 ]

Monterey Institute





Ex) f = 40. hertz. V = ?



(1) 13 m/s (2) 27 m/s (3) 60. m/s (4)120 m/s

Jan 2002 Test




V = fλ



V = 40. Hz(1.5 m)




(3) 60. m/s








Ex) Period = 5.0 sec. V = 20. m/s

Wavelength = ?


V = fλ


Need f????



T = 1/f


 5.0 sec = 1/f


f = .20 Hz


V = fλ


20. m/s = (.20 Hz)λ


= 1.0 x 102 m




3. Velocity sound = 3.3 x 102 m/s

(Air, Reference Table, room temperature)



School Blocks YouTube? Use link below.

Jet breaking speed of sound
Cambridge U.



"A "sonic boom"

is heard when a

plane exceeds

the speed of sound. "

School blocks YouTube?  Download file below.








Velocity light in a vacuum



= 3 x 108 m/s
(Reference Table)

Intracloud lightnings over Toulouse (France).
Original source is Image:Lightnings sequence 2.jpg,



About how many times faster is
than sound?



p. 1 Reference Table






About 1 million times





Gap between time you see lightning and time you hear thunder tells ....



... distance of lightning




If time gap is small?



Lightning is close




Large gap of time?






Lightning far away





Did you know ...

Every 5 seconds gap = 1 mile

'...you can approximate the storm's distance in miles by counting the seconds between the lightning and thunder and dividing by five. It takes about five seconds for the sonic boom to travel one mile, so if you see the sky illuminated by a streak of lightning and count 10 seconds until you hear the low rumble of the thunder, the storm is about two miles away.'

- Ask Yahoo




Vibrating Tuning Fork - Slow Motion

Drdanku YouTube Channel

School blocks YouTube?

Tuning Fork Vibration.mp4

Wavelength, frequency,
period, speed, amplitude.

Which 3 are determined by the source of a wave?





frequency, period, amplitude.




Source Medium
frequency speed
period wavelength










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