Answer:
u = 13.67 m/s
Step-by-step explanation:
given,
window height = 2 m
window is 7.5 m off the ground on its path up
total distance from the ground to pass the window = 2 + 7.5 = 9.5 m
time taken to go past the window = 1.30 s
using equation of motion



u = 13.67 m/s
hence, the initial velocity of the ball is equal to 13.67 m/s