The ball's height y at time t is
y = (22.1 m/s) t - 1/2 gt ²
where g = 9.80 m/s² is the magnitude of the acceleration due to gravity.
Solve for t when y = 10 m:
10 m = (22.1 m/s) t - 1/2 gt ²
→ t = 0.510 s or t = 4.00 s
The first time refers to when the ball first reaches 10 m on its way up, so t = 4.00 s and the answer is A.
