3 A speaker is attached to one end of a horizontal string“. The other end passes over a frictionless pulley andis held taught by a mass m. The distance between

the speaker and the pulley is 1.2m. The string has a linearmass density of 1.6g/m and the frequency of the speaker is 120HZ. What must the mass m be if the string is tooscillate in its fourth harmonic? In your solution, you must draw a useful well labelled picture (mostly® done for you here) and sketch the standing wave pattern. Prove the units work. Ans. 0.846kg