Question

An anchored boat is rocked by waves whose crests are 100 m apart and whose velocity is $25m/s$. How often do the crests reach the boat?

• A. $0.8sec$
• B. $4sec$
• C. $75sec$
• D. $2500sec$

Answer 1

The correct option is B $4sec$

Given that,

The distance between two consecutive crests is 100 m. This means that the wavelength of the wave is 100 m.

The velocity of the wave = 25 m/s

We have,

$velocity=\frac{wavelength}{timeperiod}$

Therefore,

$Timeperiod=\frac{wavelength}{velocity}$

$timeperiod=\frac{100}{25}=4sec$