Physics homework. help me

Question

A fisherman anchors his boat in a lake 500m from shore. The boat rises and falls 12 times in 1 minute. He observes that it takes 180s for a wave to reach the shore.

 

What is the frequency for the wave?

 

How far apart are the wave crests?

Answer 1

Given

Distance, s = 500 m

Time, t = 180 s

Calculate the speed of the boat:

v = s/t

v = 500/180

  = 2.778 m/s 

Calculate the frequency :

f   =  number of revolutions /time

   = 12/60

  = 0.2 s^-1

Therefore, the frequency is 0.2 s^-1

Calculate the crests.

 λ =v/f

    = 2.778/0.2

    = 13.89 m 

Therefore, the wave crests are 13.89 m apart 

Comments

Thank you for your answer! but I have a question. The formula of frequency is 1/T. I don't understand "12 / 60" part. Confusing. help me

---

Frequency ,f  =  number of revolutions /time

                      =12/60

                       =1/5

                        =0.2  s^-1

---

f   =  number of revolutions /time

    = 12/1 min

    = 12 /60 seconfs

   = 0.2 S^-1