A long string is moved up and down with simple harmonic motion with a frequency of 46 Hz. The string is 579 m long and has a total mass of 46.3 kg. The string is under tension of 3423 N and is fixed at both ends.
(a) Determine the velocity of the wave on the string.
(b) What length of string, fixed at both ends, would create a third harmonic standing wave?