Question

A fisherman fishing from a pier observes that the float on his line bbobs up and down, taking 2.4s to move from its highest point to its lowest point. he also estaimtes that the distance between adjacent wave crests is 48m. What is the speed of the waves going past the pier?

Answer 1

Answer:

Speed of he wave is equal to 40 m/sec

Explanation:

We have given distance between adjacent crest is 48 m

Distance between adjacent crest is equal to half of the of the wavelength

So $\frac{\lambda }{2}=48$

$\lambda =96m$

Time period is given T = 2.4 sec

So frequency $f=\frac{1}{T}=\frac{1}{2.4}=0.4166Hz$

We have to find the speed of wave

Velocity is given by $v=\lambda f=96\times 0.4166=40m/sec$

So speed of the wave will be equal to 40 m/sec

Answer 2

Answer:

Explanation:

The problem is based on speed of transverse waves formed on the surface of water. Time to travel from crest to next trough is 2.4s . So time to travel from crest to next crest will be two times 2.4 s . That is 4.8 s.  

Time to travel distance between two consecutive crest = 4.8s

distance between two consecutive crest is 48 m ( given )

velocity of wave = distance / time

= 48 / 4.8

= 10 m /s .

velocity of wave = 10 m /s.