Question

A ball is thrown from a height of 65 meters with an initial downward velocity of 10/ms . The ball's height h (in meters) after t seconds is given by the following. h=65-10t-5t^2 How long after the ball is thrown does it hit the ground? Round your answer(s) to the nearest hundredth. (If there is more than one answer, list them)

Answer 1

So you are asked to find t when the ball hits the ground, so set the equation to 0.
0=65-10t-5t^2