Solve
-A Rocket Is Launched from the Top of a Cliff

Multiple Choice

Solve.
-A rocket is launched from the top of a cliff that is 80 feet high with an initial velocity of 80 feet per second. The height, $\mathrm { h } ( \mathrm { t } )$ , of the rocket after $\mathrm { t }$ seconds is given by the equation $\mathrm { h } ( \mathrm { t } ) = - 16 \mathrm { t } ^ { 2 } + 80 \mathrm { t } + 80$ . How long after the rocket is launched will it strike the ground? Round to the nearest tenth of a second, if necessary.

A) $6.5 \mathrm { sec }$
B) $6.2 \mathrm { sec }$
C) $7.2 \mathrm { sec }$
D) $5.9 \mathrm { sec }$