1-12 Standing waves and resonances
A string of length 1.0 m and mass 9.0 g is
fixed at one end to a vibrator and at the other end to a hanging mass
through a pulley, as shown in the figure. The frequency of the vibrator is
fixed at 60 Hz. Find the mass of the weight that must be hung from the
string, if it is to resonate in the second harmonic.