If a staircase has five steps each 1.45m high and 1.5m wide. A ball is placed on the top of the staircase what maximum (horizontal) velocity be given to the ball so that it directly hits the lowest plane?
Man, those are some giant steps!
I assume you want the ball to hit the bottom just pas the lowest step.
the ball has to drop 5*1.45 = 7.25 m while it travels horizontally 5*1.5 = 7.5 m.
So, how long does it take to fall 7.25m? 4.9t^2 = 7.25
Use that time to find the horizontal speed so it covers 7.5m.