Answer
The gravitational force on the brick is proportional to mass (the greater the mass, the greater the force). But the acceleration is the same:
For complete brick:
$F=mg=m*a$
$a = g\ m/s^2$
For half brick:
$(m/2)g = (m/2)a$
$a = g\ m/s^{2}$
Work Step by Step
They both fall with the same acceleration.
(We are neglecting air resistance here.)
