If a sound wave travels 680 m in 2 seconds and has a frequency of 400 hz, what is the wavelength of the wave?

Answer: 0.85 meters (with and without sigfigs)

Explanation: To find the wavelength, you just have to switch around the equation for wave speed: v (wave speed) = λ (wavelength) * f (frequency) so λ (wavelength) = v (wave speed) / f (frequency). You don't have the wave speed but you can calculate it. Since wave speed is measured in meters/second or m/s, you just have to divide the amount of meters you were given by the amount of seconds. You will get 340 m/s. Next, you have to plug the values into the equation: λ (wavelength) = 340 m/s (wave speed) / 400 Hz (frequency). The answer is 0.85 meters (seconds cancel) and has the correct number of significant figures.