Question

in the middle of math class, maxs pencil rolls off of his desk and onto the ground 2.5 feet below. which equation can you use to find how many seconds it takes for the pencil to hit the ground? if an object falls from s feet above the ground, the objects height in feet, h, after t seconds can be modeled by the formula h = -16t² + s. 0 = -16t² + 2.5 0 = -16t² + 2.5t to the nearest tenth of a second, how long does it take for the pencil to hit the ground? seconds

Explanation:

Step1: Set height to 0 when hitting ground

$0 = -16t^2 + 2.5$

Step2: Solve for \(t^2\)

$16t^2 = 2.5 \implies t^2 = \frac{2.5}{16} = 0.15625$

Step3: Take square root for \(t\)

$t = \sqrt{0.15625} \approx 0.395$

Step4: Round to nearest tenth

$t \approx 0.4$

Answer:

0 = -16t² + 2.5, 0.4