posted by Leasha .
A ball is thrown straight up into the air with a velocity of +20.5 m/s. Find the velocity of the ball after 2.5 s.
v = Vi - g t
v = 20.5 - 9.8 (2.5)
v = 20.5 - 24.5 = -4.0
Of course if it started at the ground, the final velocity is zero because it hit the ground :)