After soccer practice, Coach Miller goes to the roof of the school to retrieve the errant soccer balls. The height of the school is 3.5 m. He kicks a soccer ball which leaves the roof with a horizontal velocity of 15 m/s. Ignoring air resistance, which of the following values is the horizontal velocity of the ball just before it lands on the ground?

Elimination Tool

A 17 m/s
B 15m/s
C 9.8 m/s
D 8.3 m/s

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

it is called kinetic energy