Awater wave has a frequency of 9 hz and a wavelength of 5 m.
(a) what is the period of these waves?
(b) what is the wave velocity?
m/s

Part a)

Part b)

Explanation:

Part a) What is the period of these waves?

we know that

Since wave frequency (f) is the number of waves per second, and the period (T) is essentially the number of seconds per wave, the relationship between frequency and period is

we have

Remember that

1 Hz is one cycle (or one wave) per second

so

Part b) What is the wave velocity?

we know that

The speed of a wave (v)  is equal to the frequency multiplied by the wavelength

we have

so

v=ir = 3x15 =45 v

i think the answer is a, hope this : )