Use the Position Equation $s = - 14 t ^ { 2 } + v _ { 0 } t + s _ { 0 }$

Multiple Choice

Use the position equation $s = - 14 t ^ { 2 } + v _ { 0 } t + s _ { 0 }$ , where $S$ represents the height of an object (in feet) , $V _ { 0 }$ represents the initial velocity of the object (in feet per second) , $S _ { 0 }$ represents the Initial height of the object (in feet) , and $t$ represents the time (in seconds) .
A projectile is fired straight upward from ground level $\left( s _ { 0 } = 0 \right)$ with an initial velocity of $112$ feet Per second. At what instant will it be back at ground level?

A) $t = 10 \mathrm { Sec }$
B) $t = 8 \mathrm { Sec }$
C) $t = 7 \mathrm { Sec }$
D) $t = 6 \mathrm { Sec }$
E) $t = 9 \mathrm { Sec }$