Question

Two canoes are 10 m apart in a lake. Each bobs up and down with a period of 4.0 s. When one canoe is at its highest point, the other canoe is at its lowest point. Both the canoes are always within a single cycle of waves. Determine the speed of the wave.

• A. 2.5 m/s
• B. 5 m/s
• C. 40 m/s
• D. 4 m/s

Answer 1

The correct option is B 5 m/s


As the two canoes are in the same cycles of waves, when one of them is at the highest point of the wave, that is the crest, the other is at the lowest, that is, the trough. The distance between the two is equal to half of the wavelength of the wave.
Frequency of wave $=\frac{1}{4}Hz$
Wavelength of wave $=\lambda =2\times 10=20m$
Velocity of wave $=f\lambda =5m/s$