A boat at anchor is rocked by waves whose crests are `100 m` apart and whose speed is `25 m//s`. These waves reach the boat once every :

Options

A. `0.25 s`
B. `4.00 s`
C. `2500 s`
D. `1500 s`

Answer

B

Explanation

`lamda = 100 m, v = 25 m//s, v = (v)/(lamda) = (25 m//s)/(100 m) = 0.25 s^-1`. Clearly, `T = (1)/(v) = (1)/(0.25 s^-1) = 4 s`.