physics
posted by mae .
A ball is thrown upward from the top of a 24.4mtall building. The ball's initial speed is 12 m/s. At the same instant, a person is running on the ground at a distance of 30.2 m from the building. What must be the average speed of the person if he is to catch the ball at the bottom of the building?
PLEASE HELP!!!!!!! :)

find the time it takes the ball to get to the bottom
Hf=hi+vi*t1/2 g t^2
0=24.4+12*t4.8 t^2
use the quadratic equation to find time of fall t.
Now, how fast does the person run? v=30.2/timet