Answer
The acceleration is $g$. Note that the acceleration does not depend on the mass of the sandbag.
Work Step by Step
Let the mass of the sandbag be $m$. We can use Newton's second law to find the acceleration:
$\sum F = ma$
$mg = ma$
$a = g$
The acceleration is $g$. Note that the acceleration does not depend on the mass of the sandbag.
