Question

1) A projectile is thrown upward so that its distance above the ground after t seconds is

Answer 1

Answer:

After 22 seconds the projectile reach its maximum height of 4,840 units

Step-by-step explanation:

we have

$h(t)=-10t^{2}+440t$

This is a vertical parabola downward (because the leading coefficient is negative)

The vertex is a maximum

Find out the coordinates of the vertex

Convert the quadratic equation in vertex form

Factor -10

$h(t)=-10(t^{2}-44t)$

Complete the square

$h(t)=-10(t^{2}-44t+22^2)+(10)(22^2)$

$h(t)=-10(t^{2}-44t+22^2)+4,840$

Rewrite as perfect squares

$h(t)=-10(t-22)^{2}+4,840$

The vertex is the point (22,4,840)

therefore

After 22 seconds the projectile reach its maximum height of 4,840 units