You dip your finger into a pan of water twice each second, producing waves with crests that are separated by 0.19 m. Determine the frequency of. . .these water waves. Answer in units of Hz
Frequency is simply cycles per second, or Hertz (Hz). Since you dip your finger in the water twice per second, the frequency is 2 Hz.
The velocity of a wave (v) is equal to the length of the wave (l) times the frequency (Hz), or v=lf. Since crest to crest is separated by 0.19 meters, that can be assumed to be the length of the wave. In this case, the velocity of the resulting waves is
v = (0.19 m)*(2 1/sec) = .38 m/sec