Problem $4.$ For a specific settling tank, the critical settling velocity is $0\mathrm{.}02$m$/$s$.$ Please determine whether the following particles can be removed in the sedimentation or not.

$($a$)$ Particle A entering the settling zone from the top edge and having a settling velocity of $0\mathrm{.}01$m$/$s

$($b$)$ Particle A entering the settling zone from the midpoint of the inlet zone and having a velocity of $0\mathrm{.}04$m$/$s

$($c$)$ Particle C entering the settling zone form the top edge and having a settling velocity of $0\mathrm{.}03$m$/$s