Question

A firecracker shoots up from a hill 165 feet high with an initial speed of 110 feet per second. Using the formula H(t) = −16t2 + vt + s, determine how long it will take the firecracker to hit the ground. (4 points)

7.2 seconds
7.5 seconds
7.8 seconds
8.1 seconds

Answer 1

v = initial velocity

so

v = 110

Answer 2

s = initial height

s = 165

Answer 3

this means

H(t) = −16t2 + vt + s

becomes

H(t) = −16t2 + 110t + 165

Answer 4

your next step is to plug in H(t) = 0 and solve for t

H(t) = -16t^2 + 110t + 165

0 = -16t^2 + 110t + 165

Answer 5

^ Ditto :)

Answer 6

lol

Answer 7

@jim_thompson5910 Pretty much said it so that's all I could say :)

Answer 8

so what do you get when you solve for t?

Answer 9

i got 8.1 @jim_thompson5910

Answer 10

same here, nice work

Answer 11

nice work too

Answer 12

thx