Answer:
A) 17 m/s
Explanation:
Given;
height of school roof, h = 3.5 m
initial horizontal velocity of the ball, u = 15 m/s
let final horizontal velocity or horizontal velocity of the ball just before it lands on the ground = v
Then, we calculate final horizontal velocity by applying kinematic equation;
v² = u² + 2gh
v² = 15² + 2 x 9.8 x 3.5
v² = 225 + 68.6
v² = 293.6
v = √293.6
v = 17.13 m/s
Therefore, the horizontal velocity of the ball just before it lands on the ground is 17.13 m/s.
A) 17 m/s