Question

In watching a transverse wave go by, an observer notes that 13 crests go by in a time of 3.0 s. If the distance between two successive crest is measured to be 0.75 m, (a) what is the speed of the wave? (b) What is its period?

Answer 1

(a) Let's first find the period of the wave:

$$T=\dfrac{3\ s}{13\ crests}=0.23\ s.$$

Then, we can find the frequency of the wave:

$$f=\dfrac{1}{T}=\dfrac{1}{0.23\ s}=4.35\ Hz.$$

Finally, we can find the speed of the wave:

$$v=f\lambda=4.35\ Hz\cdot0.75\ m=3.26\ \dfrac{m}{s}.$$

Answer:

$v=3.26\ \dfrac{m}{s}, T=0.23\ s.$