Question 17325
The formula for this is {{{y = -16t^2 + 2304 }}} for t>=0.


When it hits the ground, y=0.
{{{0 = -16t^2 + 2304 }}} 

{{{16t^2 = 2304 }}} 

{{{t^2 = 2304/16 = 144}}}, for t>=0

{{{ t=12}}} seconds.


Also, see graph below:

{{{graph (300,300, -3, 15, -100, 2500, -16x^2+ 2304) }}}


R^2 at SCC