Question

A skateboarder leaves a 12-foot tall ramp with an initial vertical velocity of 8 feet per sen

Answer 1

To answer this, we substitute 12 ft to the f(h) in the given equation,   
f(h) = -8t² + 8t + 12 = 12

Subtracting 12 from both sides of the equation will give us an answer of,

-8t² + 8t = 0

Then, we transpose 8 to the other side and divide the equation by -8 and t, we get an answer of t = 1 second. 

Answer 2

Answer:

Below in bold.

Step-by-step explanation:

When he lands h = 0  so

-8t^2 + 8t + 12 = 0

Solving for t

t = [-8 +/- sqrt(8^2 - 3*-6*12)] / -16

t = 1.82 seconds.