posted by rachel .
A hot-air balloon is rising upward with a constant speed of 2.50 m/s. When the balloon is 3.00 m above the ground, the balloonist accidentally drops a compass over the side of the balloon. How much time elapses before the compass hits the ground?
Solve this quadratic equation for t:
y = 2.50t -4.9t^2 +3.00 = 0
Take the positive one of the two roots.