A ball thrown horizontally at 13.0m/s from the roof of a building lands 21.4m from the base of the building. How tall is the building?

Answer 1

first do the horizontal problem with constant horizontal speed of 13 for 21.4 m to get time in air

distance = speed * time
t = 21.4 /13.0

now we know it fell for time t

h = (1/2) g t^2
h = (1/2) (9.81) (21.4/13.0)^2 meters