A ball is thrown horizontally from the top of a 85 m building and lands 140 m from the base of the building. Ignore air resistance, and use a coordinate system whose origin is at the top of the building, with positive y upwards and positive x in the direction of the throw.
a) How long is the ball in the air in seconds?
b) What must have been the initial horizontal component of the velocity in m/s?
c) What is the vertical component of the velocity just before the ball hits the ground in m/s?
d) What is the magnitude of the velocity of the ball just before it hits the ground in m/s?