Walking along the beach, you notice that a new wave reaches the shore every 3.8 s, and you estimate the wave crests to be 2.5 m apart. At what wave speed c are the waves moving?

The waves are moving at the speed of 0.66 m/s

Explanation:

1. dа ta:

a) period = 3.8 s

b) λ = 2.5 m

c) c = ?

2. Physical principles and formula:

The time that it takes a wave to complete a cycle is called period. the unit of period is second. The period is the inverse of the frequency, i. e. period = 1 / frequency The distance between two consecuitve crests is the wavelength The equation that relates speed (s), wavelength (λ), and period (T) is:

distance = speed * time

wavelength = speed * T

λ = c * T

meter = (meter/second) * second

m = (m / s) * s

3. Solution:

λ = c * T ⇒ c = λ / T c = 2.5 m / 3.8 s = 0.66 m/s