Chapter 6 - Section 6.7 - Quadratic Equations and Problem Solving - Exercise Set - Page 467: 35

9.5 seconds

$h=-16t^2+1444$ $0=-16t^2+1444$ $0=-4(4t^2+361)$ $0/-4=-4(4t^2-361)/-4$ $0=4t^2-361$ $0=(2t+19)(2t-19)$ $2t-19=0$ $2t=19$ $2t/2=19/2$ $t=19/2$ $2t+19=0$ $2t=-19$ $2t/2=-19/2$ $t=-19/2$ (not valid since we can't have negative time)