posted by eric .
A tennis ball is held stationary and then dropped from the roof of a tall building. What will be its velocity after 3.0 s?
V = -g*t, where
g = 9.8 m/s^2 (on Earth)
The minus sign is because the acceleration is in the negatve direction, assuming + is up.
V(t=3s)= -29.4 m/s
Air resistance has been neglected. That will slow it down.