Motion in two dimension

Question

Three balls are sequentially thrown at the same instant from top of a building,at the same speed Ball 1 is thrown vertically upwards ball 2 is thrown vertically downward and ball 3 is thrown horizontally
A) do all balls reach the ground at the same time? If not in which order do they fall?
B) do they strike the ground at the same speed? List their velocities in order if magnitude.
C) do the masses of the balls affect the times they take to fall?

Answer 1

(A) The ball thrown vertically down arrives first, followed by the ball thrown horizontally, and last the ball thrown vertically up. (B) Total energy of each ball must be conserved, so if they started from the same height at the same speed, they will all reach the same new speed at a different height. The change in speed will depend only on the change in height, and not on the masses of the balls. (C) The balls fall under the constant acceleration of gravity at sea level, which does not depend on their masses.