Question 871465
If a ball is shot upward from ground level with an initial velocity of 136 feet per second, after t seconds, its height h in feet is given by the formula h=-16t^2 + 136t. After how many seconds will it hit the ground?

If a ball is shot upward from ground level with an initial velocity of 136 feet per second, after t seconds, its height h in feet is given by the formula 


h=-16t^2 + 136t. 
At two times the ball will be on ground

once when starting and once when it lands

h=0
h=-16t^2 + 136t. 
16t^2=136t
t=136/16
t=17/2
t=8.5 seconds