Two small boats are `10m` apart on a lake. Each pops up and down with a period of 4.0 seconds due to wave motion on the surface of water. When one boat is at its highest point, the other boat is its lowest point. Both boats are always within a single cycle of the waves. The speed of the waves is:

Options

A. `2.5 m//s`
B. `5.0 m//s`
C. `14 m//s`
D. `40 m//s`

Answer

B

Explanation

Distance between boat `= (lambda)/(2) = 10 m`
`rArr = 20m`
time penod, `T = 4` sec .
`:. V = lambda//T = 20 m //4 sec = 5 m//s`.