Question

H(t)=-16t^2+24

So I have to find how long (in seconds) it will take a tool to fall to the ground from a height of 24 feet. I am using the equation h(t)=-16t^2+24 to find it but I'm not sure how to solve it or where to even get started! Any help would be great thank you!

Answer 1

when h(t)=0, it hits the ground

solve
0=-16t^2+24
factor out -8
0=-8(2t^2-3)
we know that
0=2t^2-3 since factors have to multiply to 0
add 3 to both sides
3=2t^2
divide both sides by 2
1.5=t^2
sqrt both sides
1.2247=t

after about 1.2247 seconds it will hit the ground