A buoy floating on a lake is seen to rise and fall 20 times in a minute. What is the frequency with which the buoy oscillates?

Question

A buoy floating on a lake is seen to rise and fall 20 times in a minute. What is the frequency with which the buoy oscillates?

What is the period of motion?

If water waves on the lake are traveling at 4 m/s, what is the spacing between wave peaks? What is the technical name for this quantity?

Water waves tend to slow down when they reach shallower water. If the water waves slow by 15%, what will be the new spacing between wave peaks?

Answer 1

a) f = cycles/time = 20 cycles/1 minute *(1minute/60s) = .333 cycles/s or Hz.

b) T = 1/f in secs/cycle

c) v = λf so λ = v/f in meters

d) λ is wavelength

e) λ' = .85v/f or .85λ