Question

Cindy shoots a bottle rocket straight up into the air such that its height h, in feet, at time t, in seconds, is given by the function h of t = negative 16 times t squared plus 85 t + 5.. During what interval will the rocket be at least 43 feet above the ground?

Answer 1

t = [0.493,4.2]

Explanation:

The height of the rocket straight up into the air is given by :

`h(t)=-16t^2+85t+5`

We need to find the interval the rocket be at least 43 feet above the ground.

`43\ge -16t^2+85t+5\\\\t\ge 0.493\ and\ t\le 4.82\ s`

So, the required interval during which the rocket is at least 43 feet above the ground is [0.493,4.2].