A rocket is launched from atop a 105-foot cliff with an initial velocity of 156 ft/s. The height of the rocket above the ground at time t is given by h = - 16t2 + 156t + 105. When will the rocket hit the ground after it is launched? Round to the nearest tenth of a second.

4.9 s

9.8 s

0.6 s

10.4 s

Question

Maverick Chase

Mathematics

6 April, 19:59

A rocket is launched from atop a 105-foot cliff with an initial velocity of 156 ft/s. The height of the rocket above the ground at time t is given by h = - 16t2 + 156t + 105. When will the rocket hit the ground after it is launched? Round to the nearest tenth of a second.

4.9 s

9.8 s

0.6 s

10.4 s

+1

Answers (1)

Know the Answer?

Lassie · Answer 1

H = - 16t2 + 156t + 105, when t = t', the time where the rocket hit the ground after it is launched, so 105 = - 16t'2 + 156t' + 105, so - 16t'2 + 156t' = 0 implies t' = 0 or - 16t' + 156 = 0, equivalent to t'=9.75, so the answer is

b) 9.8 s

A rocket is launched from atop a 105-foot cliff with an initial velocity of 156 ft/s. The height of the rocket above the ground at time t is given by h = - 16t2 + 156t + 105. When will the rocket hit the ground after it is launched? Round to the nearest tenth of a second.4.9 s9.8 s0.6 s10.4 s