Answer:
16 waves
Step-by-step explanation:
This is actually pretty easy to understand.
First we have the frequency "f" of the waves which is 0.571429 Hz and we want to know how many waves will hit the beach in 28 s. To know this, we need to know the period time of the waves, this can be calculated with the frequency and the following expression:
T = 1/f
With this expression we can calculate the period time of the waves. So replacing the data:
T = 1 / 0.571429
T = 1.749999 s
Now that we have the period, this number means that every 1.75 s, a wave hit the beach. Now to know the number of waves in 28 s, we just divide the period with the given time:
n = t/T
Replacing we have:
n = 28 / 1.749999
n = 16 waves
This is the number of waves that hit the beach in 28 s.