Step-by-step explanation:
The given data is as follows.
 Initial velocity; u = 0, Final velocity; v = 19.6 m/s
 time; t = 2 seconds
As the relation between initial velocity, final velocity and acceleration is as follows.
 v = u + at
Hence, putting the given values into the above formula as follows.
 v = u + at
 19.6 m/s = 0 + 
 
 a = 9.8 
 
Thus, we can conclude that acceleration of the dropped ball is 9.8 
.