physics
posted by haylee .
While watching ocean waves at the dock of the bay, Otis notices that 8 waves pass beneath him in 30 seconds. He also notices that the crests of successive waves exactly coincide with the posts that are 3 meters apart. What are the period, frequency, wavelength, and speed of the ocean wave?

Frequency is the number of waves that pass by in one second. You know that 8 waves pass by in 30 seconds. How many pass by in 1 second?
Period is the time it takes for one wave to pass by. Period is the inverse of frequency (T = 1/f).
Wavelength is the distance measured from crest to crest.
The speed of the waves can be calculated by multiplying wavelength by the frequency. 
frequency is 8/30=./2
period is =1/(8/30)=1/(./2)=5
wavelength is 30 meters and speed of ocean waves is according to above formula becomes (30*./2)=6 m/s
good luck students of physics more study and very more practice physics problems.
alhosseiny from iran(tehran)