Math

posted by .

a firecracker is fired from the ground. The height of the firecracker at a given time is modeled by the function h(t) =-5t^2+50t, where h(t) is the height in metres and t is the time in seconds. When will the firecracker reach a height of 45m ?

  • Math -

    solve for t in

    45 = -5t^2 + 50t
    5t^2 - 50t + 45 = 0
    t^2 - 10t + 9 = 0
    (t-9)(t-1) = 0

    it will reach 45m on the way up at t=1, and on the way back down at t=9.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Math

    A firecracker is launched straight up, and its height is a function of time, h(t)= -14^2 + 112t, where h is the height in feet and t is the time in seconds with t=0 corresponding to the instant it launches. What is the height 5 seconds …
  2. Math

    Can someone help me and verify if the answer I picked is correct?
  3. Math

    The height of a ball at a given time is modelled by the function h(t)=5t^2+7t+1 where h(t) is in metres and time is in seconds . When will the ball hit the ground
  4. MATH

    A Ferris wheel completes one revolution every 90 s. The cars reach a maximum of 55 m above the ground and a minimum of 5 m above the ground. The height, h, in metres, above the ground can be modeled using a sine function, where t represents …
  5. math

    a rock is thrown straight up in the air from an initial height of ho, in metres, with the initial velocity vo, in metres per second. The height in metres above the ground after t seconds is given by h(t) = -4.9t^2 + vo + ho. Find an …
  6. Math

    I have done two parts but no idea how to the third one. The height, h, in meters, of a firecracker fired into the air can be modeled using the function h(t)=-5(x-4)^2+85, where t is the time, in seconds, after the firecracker is fired. …
  7. Math - Geometry

    An object is launched from certain height into the air. The height is modeled by the the function h(t) = -4.8t^2+23t+20. The time (t) is measured in seconds. A) What is the maximum height?
  8. math is my answer correct

    Is my answer correct?? The function h(t) = 2 + 50t - 1.862t^2, where h(t) is the height in metres and t is the time in seconds, models the height of a golf ball above the planet Mercury's surface during its flight. A) What is the maximum
  9. MATH HELP

    A soccer ball is kicked toward the goal. The height of the ball is modeled by the function h(t) = −16t2 + 48t where t equals the time in seconds and h(t) represents the height of the ball at time t seconds. What is the axis of …
  10. algebra

    A soccer ball is kicked toward the goal. The height of the ball is modeled by the function h(t) = −16t2 + 48t where t equals the time in seconds and h(t) represents the height of the ball at time t seconds. What is the axis of …

More Similar Questions