Answer
(a) $32N$
(b) increase
Work Step by Step
(a) We can find the required force as follows:
$F=(m_{top}+m_{bottom})\mu_sg$
We plug in the known values to obtain:
$F=(2.0+5.0)(0.47)(9.81)$
$F=32N$
(b) We know that if we increase $m_{top}$ then F will increase because the larger mass requires a larger force to continue the motion with constant acceleration.
