Answer :
Answer:
15.01 m/s
Explanation:
Applying newtons equation of motion,
v² = u²+2gs.................. Equation 1
Where v = final velocity, u = initial velocity, s = distance, g = acceleration due to gravity.
Given: u = 21 m/s, s = 11 m
Constant: g = -9.8 m/s² ( g is negative because the stone against the force of gravity).
Substitute these values into equation 1
v² = 21²-2(11)(9.8)
v² = 441-215.6
v² = 225.4
v = √225.4
v = 15.01 m/s