Question

a ball is thrown horizontally from the roof of a building 45.0 m tall and lands 24.0 m from the base. What was the ball´s initial speed?

Answer 1

ball drops 45m under g=10m/s/s

45=1/2x10xt^2 ... application of kinematic equaion from rest

90/10=t^2

t=3

24.0 m in 3 secs => 8m/s no air resistance