Question

The flight of javelin released 6.5 feet from the ground at an initial velocity of 68 feet per second is modeled by the function h=-16^2+6.5 where h is the height of the javelin in feet after r seconds . Determine how many seconds it will take the javelin to reach the maximum height and find the maximum height. Round to the nearest hundredth if necessary

Answer 1

Using the vertex of the quadratic equation, it is found that a maximum height of 78.75 feet is reached after 2.13 seconds.

What is the vertex of a quadratic equation?

A quadratic equation is modeled by:

$y = ax^2 + bx + c$

The vertex is given by:

$(x_v, y_v)$

In which:

$x_v = -\frac{b}{2a}$

$y_v = -\frac{b^2 - 4ac}{4a}$

Considering the coefficient a, we have that:

• If a < 0, the vertex is a maximum point.

• If a > 0, the vertex is a minimum point.

In this problem, the height is modeled by:

h(t) = -16t² + 68t + 6.5.

The coefficients are a = -16, b = 68, c = 6.5, and the vertex will be given by:

$x_v = -\frac{b}{2a} = -\frac{68}{-32} = 2.13$

$y_v = -\frac{b^2 - 4ac}{4a} = -\frac{68^2 - 4(-16)(6.5)}{-64} = 78.75$

A maximum height of 78.75 feet is reached after 2.13 seconds.

More can be learned about the vertex of a quadratic equation at https://brainly.com/question/24737967