Math( help please ! )

posted by .

The height of a ball thrown vertically upward from a rooftop is modelled by y=-5t^2+20t+50 , where h(t) is the ball's height above the ground , in meters , at time t seconds after the throw

a) Determine the max height of the ball

b) how long does it take for the ball to reach its max height

c) How high is the rooftop

  • Math( help please ! ) -

    y = 5(10 + 4t - t^2)

    max height achieved where t = -b/2a = 2
    y(2) = -5(4) + 20(2) + 50 = 70

    as above, when t=2

    The rooftop is the ball's initial height. That is, when t=0. So, 50 ft.

  • Math( help please ! ) -

    thank you so much

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. phy

    A blue ball is thrown upward with an initial speed of 20.6 m/s, from a height of 0.8 meters above the ground. 2.5 seconds after the blue ball is thrown, a red ball is thrown down with an initial speed of 8.2 m/s from a height of 23.7 …
  2. Math( help please ! )

    The height of a ball thrown vertically upward from a rooftop is modelled by h(t)=-5t^2=20t=50, where h(t) is the ball's height above the gorund,in meters, at time t seconds after the throw a) determine the maximum height of the ball …
  3. Algebra

    If a ball is thrown vertically upward from a height of 56ft. above ground with an initial velocity of 40ft. per second, then the height of the ball above ground t seconds after it is thrown is given by f(t)=-16t^2 + 40t +56. How many …
  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. college

    A blue ball is thrown upward with an initial speed of 19.8 m/s, from a height of 0.5 meters above the ground. 2.4 seconds after the blue ball is thrown, a red ball is thrown down with an initial speed of 7.9 m/s from a height of 22.5 …
  6. physics

    A red ball is thrown down with an initial speed of 1.2 m/s from a height of 25.0 meters above the ground. Then, 0.6 seconds after the red ball is thrown, a blue ball is thrown upward with an initial speed of 22.9 m/s, from a height …
  7. Physics

    A red ball is thrown down with an initial speed of 1.3 m/s from a height of 28.0 meters above the ground. Then, 0.6 seconds after the red ball is thrown, a blue ball is thrown upward with an initial speed of 24.7 m/s, from a height …
  8. math

    An object that is falling or vertically projected into the air has it height, in feet, above the ground given by the formula below, where s is the height in feet, Vo is the original velocity of the object, in feet per second, t is …
  9. Pre-Calc

    ball thrown vertically upward with an initial velocity of 80 ft per second. The distance s(in ft) of the ball from the ground after t seconds is s=80t-16t^2. a. draw the illustration. b. for what time interval is ball more than 96 …
  10. math

    the height of a ball thrown vertically upward from a rooftop is modelled by h(t)=-5t^2 +20t+50. Determine the maximum height of the ball.

More Similar Questions