Apitcher threw a baseball straight up at 35.8 meters per second. what is the ball's velocity after 2.50 seconds?

Ok the velocity of an object in free fall is given by the equation :

v=v0-gt, where v0 is the original velocity, g is the gravitational constant (9.8 m/s^2) and t is the time. 

so, we substitute values into this equation. v=35.8-9.8*2.5; v=11.3 m/s