Question

You are at a pool party and notice that 2 waves pass by a floating ball in 4 seconds. If the distance between each wave crest is 2 meters, what is the speed of the waves? (Hint: you will need to calculate the frequency first.)
Note: wave speed (m/s) = Frequency (Hz) x Wavelength (m)
To calculate Frequency=Number of waves/Time
A. 1 m/s
B. 6 m/s
C. 2 m/s
D. 1.5 m/s

Answer 1

Number of waves = 2, time = 4 s → frequency f = 2/4 = 0.5 Hz.
Wavelength λ = 2 m.
Speed v = f·λ = 0.5·2 = 1 m/s.

Answer: A.