To answer this question, we will use the equation of motion:
v = u + at where:
v is the final velocity that we need to calculate
u is the initial velocity of the stone = 0 m/sec
a is the acceleration = 9.8 m/sec^2
t is the time = 8 seconds
Substitute in the above equation to get the final velocity as follows:
v = 0 + 9.8(8) = 78.4 m/sec
Based on the above calculations:
final velocity of the stone = 78.4 m/sec