Post a New Question

Math

posted by .

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 -

    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.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Algebra

    THe function h(t)=-16t^2+v0t+h0 describes the height in feet above the ground h(t) of an object thrown vertically from a height of h0 feet, with an initial velocity of v0 feet per second, if there is no air friction and t is the time …
  2. Algebra

    THe function h(t)=-16t^2+v0t+h0 describes the height in feet above the ground h(t) of an object thrown vertically from a height of h0 feet, with an initial velocity of v0 feet per second, if there is no air friction and t is the time …
  3. Math

    A person standing close to the edge on the top of a 160-foot building throws a baseball vertically upward. The quadratic function s(t) = -16t^2 +64t + 160 models the ball's height above the ground, s(t), in feet, t seconds after it …
  4. math

    A person standing on the roof of a building throws a ball directly upward. The ball misses the rooftop on its way down and eventually strikes the ground. The function s(t) = −16t2 + 64t + 80 describes the ball’s height above …
  5. math

    an object is thrown upward from the top of a 80-foot building with a initial velocity of 65 feet per second. The height h of the object after t seconds is given by the equation h=-16t2+64t+80. when will the object hit the ground
  6. Math

    An object is projected vertically upward from the top of a building with an initial velocity of 144 ft/sec. Its distance s(t) in feet above the ground after t seconds is given by the function s(t) = −16t2 + 144t + 120. A) Find …
  7. -MATH-

    h=-16t2+80t+96 Use this position polynomial to calculate the following: 1.The height of the object after 2 seconds 2.The height of the object after 4 seconds 3.How long the object will take to reach the ground?
  8. Math

    If you are standing near the edge of the top of a 200 feet building and throw a ball vertically upward it will be modeled by the function s(t)=-16t^2+64t+200 where s(t) is the ball's height above ground in feet and t is seconds after …
  9. algebra 2

    So the dead line for my class is coming up. And I really need help for these questions! 2. Elaine shoots an arrow upward at a speed of 32 feet per second from a bridge that is 28 feet high. The height of the arrow is given by the function …
  10. Math

    Hoping Henry can help on previous prob. A ball is thrown upwards from a roof top, 80ft above the ground. It will reach a maximum vertical height and then fall back to the ground. The height of the ball from the ground at time T is …

More Similar Questions

Post a New Question