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? (5 points)
A) 8 seconds
B) 9 seconds
C) 10 seconds
D) 11 seconds

Question

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? (5 points)
A) 8 seconds 
B) 9 seconds 
C) 10 seconds 
D) 11 seconds

anonymous · Answer

What is 's'? In this type of physics equation, normally this is 'x', as in "initial displacement". Is this correct? Presuming so, you have:
$$0 = -16t^2 + 110t + 150$$

anonymous · Answer

I'm not sure how well this factors, but you can use the quadratic formula. You will only have one positive answer.