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5-81.

If the height (in meters) of an object traveling vertically is represented by the function h(t) = −4.9t2 + 21t + 3 where t is measured in seconds, determine its: Homework Help ✎

  1. Starting velocity

    Evaluate v(t) when t = 0.

  2. Starting position

    Evaluate h(t) when t = 0.

  3. Maximum height

    Since the height function is a parabola, the maximum height can be determined by using Algebra to locate the vertex. Calculus can also be used.

    The maximum height will occur at the time when v(t) = 0.

    The vertex of the parabola is located at t = –21/2(–4.9) ≈ 2.143 seconds.
    h(2.143) ≈ 25.5 m