Question

A ball is thrown from a height of40 meters with an initial downward velocity of 10 . The ball's height (in meters) after seconds is given by the following.

Answer 1

after 2 seconds

0=40-10t-5t^2

t^2+2t-8=0

(t+4)(t-2)=0

t=-4 or t=2

I think this is correct