physics
posted by Dave on .
A ball is released from a hot air balloon moving downward with a velocity of
10.0 meters/second and a height of 1,000 meters. How long did it take the ball to reach the surface of Earth? Given: g = 9.8 meters/second2.

hf=hi+vi*t+1/2 a t^2
0=100010t4.9t^2
solve the quadratic
t=(10+sqrt(100+19600))/9.8
t=150/9.8=15.3sec
check that. 
incorrect