A firecracker shoots up from a hill 150 feet high with an initial speed of 110 feet per second. Using the formula H(t) = −16t2 + vt + s, approximately how long will it take the firecracker to hit the ground?

Question

anonymous · Answer

8 seconds

 9 seconds

 10 seconds

 11 seconds

agent0smith · Answer

H(t) = −16t2 + vt + s

v would be the speed, 110. and s i think would be the height, 150, so 

 H(t) = −16t^2 + 110t + 150

set it equal to 0 and solve for t:

−16t^2 + 110t + 150 = 0

you may want to use the quadratic formula... do you know what it is?