Question

Gianna is going to throw a ball from the top floor of her middle school. When she throws the ball from 48feet above the ground, the function h(t)=-16t^2+32t +48 models the height,h, of the ball above the ground as a function of time, t. Find the zero of this function that tells us when the ball will hit the ground.

Answer 1

To find when the ball will hit the ground, we need to find the value of t when h(t) = 0 since the height above the earth will be zero when the ball hits the ground.

Substitute h(t) = 0 in the given equation:

-16t^2 + 32t + 48 = 0

Dividing both sides by -16:

t^2 - 2t - 3 = 0

Factorizing the equation:

(t - 3)(t + 1) = 0

So, the solutions are t = 3 or t = -1.

Since time can't be negative, the only solution that makes sense in this context is t = 3.

Therefore, the ball will hit the ground after 3 seconds.