Question 103591
To find when the object will hit the ground, let h=0 and solve for t


{{{0=-16t^2 + 40t + 10}}}

*[invoke quadratic_formula -16, 40, 10, "t"]



Since a negative time doesn't make any sense, the only solution is approximately 


{{{t=2.729}}}



So it will take about 2.729 seconds for the object to hit the ground