## help_people one year ago 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? Eight seconds Nine seconds 10 seconds 11 seconds

1. help_people

@LiveLaughDie @Nnesha @pooja195

2. sohailiftikhar

what is s?

3. help_people

im not sure @sohailiftikhar

4. sohailiftikhar

it should be some constant value like 5,3 etc u checked the statement clearly ?

5. sohailiftikhar

take is 5 ..now out height H=0 to find the time 0=-16t^2+vt+5

6. sohailiftikhar

now 16t^2-vt=5 put value of v from given data v=110fet/sec 16t^2-110t=5 divide whole equation with 16 to get simplest form

7. help_people

16t^2=5+110 16T^2=115 is tis correct?

8. sohailiftikhar

no where is the t with 110 ?

9. help_people

? could you just show me for my understudying @sohailiftikhar

10. sohailiftikhar

just find the value of t from the equation which i gave you ignor negative value and get +ve value that will be the answer

11. help_people

t=2.680951

12. help_people

@sohailiftikhar

13. sohailiftikhar

did u do your work correctly ? what two values you have got ? for t

14. help_people

-2.680951

15. help_people

there ya goooo @sohailiftikhar

16. sohailiftikhar

ok it's correct

17. help_people

ok I'm still not sue what the answer is :/ @sohailiftikhar

18. sohailiftikhar

lol we are not sure about s which we taken as 5 ..so take it easy it's 2 sec

19. help_people

that not one of the answers :( @sohailiftikhar

20. sohailiftikhar

21. help_people

10? @sohailiftikhar

22. sohailiftikhar

lol what ? no it can be possible it only can 2 or near it your answer is correct i'm sure ..from where u get this huh ?

23. help_people

here are the options: Eight seconds Nine seconds 10 seconds 11 seconds

24. Nnesha

setup the equation when it hits the ground h(t)=0 n v=110 and s=150 now plug in the numbers and solve the qudratic equation

25. help_people

ok

26. help_people

so im solving for s?

27. Nnesha

no solve for t they already gave you v and s value

28. help_people

what are they ?

29. Nnesha

$$\color{blue}{\text{Originally Posted by}}$$ @Nnesha setup the equation when it hits the ground h(t)=0 n v=110 and s=150 now plug in the numbers and solve the qudratic equation $$\color{blue}{\text{End of Quote}}$$ read this

30. help_people

ook so what would the formula be to solve for t ?

31. Nnesha

$\huge\rm \frac{ -b \pm \sqrt{b^2-4ac} }{ 2a }$ quadratic formula

32. Nnesha

a , b ,c values are $\huge\rm Ax^2+Bx+C=0$ A= leading coefficient b=middle term c= constant term