a water wave has frequency 0.40 Hz and wavelength 2.0m. Its speed is
L = VT,
V = L/T = L*f = 2 * 0.4 = 0.8 m/s.
To calculate the speed of a water wave, you can use the formula:
Speed = Frequency x Wavelength
Given that the frequency of the water wave is 0.40 Hz and the wavelength is 2.0 m, you can substitute these values into the formula to find the speed:
Speed = 0.40 Hz x 2.0 m = 0.80 m/s
Therefore, the speed of the water wave is 0.80 m/s.