Question

Please help quickly for 5 stars and brainliest!!

Answer 1

1.
Height h = 240 feet
We insert it into formula.
$240 = -16 t^{2} +128t$
Now we solve this for t:
$16 t^{2} -128t +240 = 0 /16 \\ t^{2} - 8t +15 =0 \\ t_{1} = 5 t_{2} = 3$

We have two answers as the rocket will pass this height on it's way up and down.

2.
Height h = 0 feet
We insert it into formula.
$0=-16 t^{2} +76t + 2$
Now we solve this for t:
$16 t^{2} - 76t -2 = 0 /2 \\ 8t^{2} - 38t - 1 = 0 \\ t_{1} = 5 t_{2} = -1$
We do not consider solution -1 as the time can not be negative. Our solution is 5s.

3.
Height at bottom of hill h = 0 feet
We insert it into formula.
$v^{2} = 64 * 0 = 0 ft/s$