The final velocity of the pebble as it hits the ground is 21.5 m/s.
We have to use the equation;
v = u + gt
Where;
v = final velocity
u = initial velocity
g = acceleration due to gravity
t = time
Since the pebble was dropped from a height, u =0 m/s, hence,
v = gt
v = 9.8 ms-2 × 2.2 s
v = 21.5 m/s
Learn more about velocity: https://brainly.com/question/8898885