Posted by **Anonymous** on Friday, July 6, 2012 at 8:26am.

An object is propelled vertically upward from the top of a 144-foot building. The quadratic function s(t)= -16t2+192+144 models the ball's height above the ground, in feet, s(t) seconds after it was thrown. How many seconds does it take until the object finally hits the ground? Round to the nearest tenth of a second if necessary.

Answer

0.7 seconds

- Math -
**Reiny**, Friday, July 6, 2012 at 8:35am
when it hits the ground, s(t) = 0

-16t^2 + 192t + 144 = 0

t^2 - 12t - 9 = 0

I will complete the square rather than use the quadratic formula

t^2 - 12t + 36 = 9 + 36

(t-6)^2 = 45

t-6 = ±√45

t = 6 ± √45

= appr -.7 or 12.7

since t > 0, it will hit the ground 12.7 after it was tossed.

## Answer this Question

## Related Questions

- Math - An object is projected vertically upward from the top of a building with ...
- Math - A person standing close to the edge on the top of a 160-foot building ...
- math - an object is thrown upward from the top of a 80-foot building with a ...
- Math - ) If you are standing near the edge of the top of a 200 ft. building and ...
- Algebra - THe function h(t)=-16t^2+v0t+h0 describes the height in feet above the...
- Algebra - THe function h(t)=-16t^2+v0t+h0 describes the height in feet above the...
- math - A person standing on the roof of a building throws a ball directly upward...
- calculus - If a ball is thrown vertically upward from the roof of 64 foot ...
- Calculus - If a ball is thrown vertically upward from the roof of 32 foot ...
- -MATH- - h=-16t2+80t+96 Use this position polynomial to calculate the following...

More Related Questions