Question

A ball is thrown up or had from a height of 15 feet with an initial velocity i'm 5 ft. Using the formula h(t) equals -16 T squared plus 5T +15 determine how long it will take the ball to hit the ground round your answer to the nearest 10th of a second

Answer 1

Explanation:

Our quadratic is

`s(t)=-16t^2+5t+15` where s(t) is the height of the ball after a certain amount of time goes by. If the ball ends up on the ground, we know that height of the ball ON the ground is 0, right? Sub in a 0 for s(t) and factor to solve for t, how long it takes the ball to hit the ground. Another way this question could be asked is "how long was the ball in the air?" Be aware of the wording!!

`0=-16t^2+5t+15`

Throw this into the quadratic formula to get

t = -.8 or that t = 1.1

Since we all know that time will NEVER be negative, the time it takes the ball to hit the ground (aka the time the ball was in the air) is 1.1 seconds.