Question

A ball is thrown from a height of 70 feet with an initial downward velocity of 4/fts. The ball's height h (in feet) after t seconds is given by the following.
h=70-4t-16t^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, use the "or" button.)

Answer 1

In this one, you must make h = 0.

You get : $-16t^2-4t+70$ which can be further simplified to $8t^2+2t-35$ if you divide all of the numbers by -2.

Here you can use the quadratic formula again!
You get the numbers to be : 1.97 and -2.22

I had made a mistake to think that negative numbers can be included but in these questions, you can't have negative numbers as your answer. So the correct answer is 1.97!