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 ]

 

 

slinkyreflections2.mov

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.

sonicboom_hi.mov

 

 

 

 

 

 

Velocity light in a vacuum

 

 

= 3 x 108 m/s
(Reference Table)

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

 


 

About how many times faster is
light
 
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.

 

 

 

Summary
Source Medium
frequency speed
period wavelength
amplitude  

 

 

 

 

 

  

 

 

 

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