Answer
Please see the work below.
Work Step by Step
(a) We know that the mass of the second body is given as
$m_2=\frac{F_c}{a}$
$\implies m_2=\frac{4.45N}{1.20m/s^2}$
$m_2=3.71kg$
Now $m_1=M-m_2$
We plug in the known values to obtain:
$m_1=16.66Kg-3.71Kg=12.95Kg$
(b) We know that
$m_2=\frac{F_c}{a}$
We plug in the known values to obtain:
$m_2=\frac{4.45N}{1.20m/s^2}$
$m_2=3.71Kg$