Answer
(a) decrease
(b) $6.93Hz,13.9Hz$$
Work Step by Step
(a) The frequencies will decrease. The reason behind this is that the wave speed and mass are inversely proportional while frequency is directly proportional to the wave speed. Thus, when mass is increased the wave speed and frequency will decrease.
(b) We know that
$v=\sqrt{\frac{F}{\mu}}=\sqrt{\frac{22.1}{0.0150/7.66}}=106.23\frac{m}{s}$
Now the fundamental frequency can be calculated as
$f_1=\frac{nv}{2L}$
$f_1=\frac{1(106.23)}{2(7.66)}=6.93Hz$
and the second harmonic is given as
$f_2=\frac{nv}{2L}$
$f_2=\frac{2(106.23)}{2(7.66)}=13.9Hz$
