(ii) a ball is thrown horizontally from the roof of a building 7.5 m tall and lands 9.5 m from the base. what was the ball’s initial speed

Initial Speed will be 7.68 m/s

Explanation:

Height of the building is given as

H = 7.5 m

now we know that ball is thrown horizontally so here initial speed in vertical direction is ZERO

so we can apply kinematics in vertical direction

now the horizontal distance covered by the ball in the same time is

so here we can use equation for uniform motion

answer; i believe the correct answer is (40,000 j) good luck