8 string p is stretched between two points on a wall separated by dist

Question

8. String P is stretched between two points on a wall separated by distance L. (a) There is a standing wave on the string. It is vibrating at a frequency equal to to its fifth harmonic.Is the midpoint of the string a node, an anti node or something else? (b) If the frequency of the second harmonic is 20 Hz what is the frequency of the fifth harmonic? (c) String Q, with the same mass per unit length of String P and having four times the tension of string P, is stretched between two points separated by distance 6L. Consider the first seven harmonics of string P and string Q. How many frequencies are common in both sets? Explain.