It not an assignment am just putting the things I learnt from your video on projectile to work. I have tried every method possible but am confused with the case of downward projection. Please kindly put me through.
Thanks.

A body is projected downward at an angle of 30 degrees to the horizontal from the top of a building 170m high. It's initial speed is 40m/s. a) How long will it take before striking the ground? How far from the foot of the building will it strike? c) At what angle with the horizontal will it strike?