A boy in a boat on a lake watches waves that seem to be an endless
succession of identical crests passing with a half second interval
between each. If every disturbance takes 1.5 sec to sweep straight
along the length of her 4.5 m long boat, what are the    fequency,    
  period,   and wavelength
of the waves???

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Request for Question Clarification by scriptor-ga on 12 Jan 2006 15:33 PST

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Regards,
Scriptor

The time between crests gives you the period.
The length of the boat and the time it takes the waves to pass it will
give you the speed of the waves.
From the period you can get the frequency, and from the frequency and
the wave speed you can get the wavelength.

Frequency:

Let T be the period, 0.5 seconds.

F = 1/T = 1/.5 = 2/s = 2 Hz

Period:

.5 seconds

Wavelength:

The speed of the wave is 4.5 m / 1.5 s = 3 m/s

Speed = Wavelength * Frequency

3 m/s = Wavelength * 2

Wavelength = 3 m