Aprojectile is fired straight up from ground level. after t seconds it's height is above the ground is h feet where h=-16t^2+144t. for what time period is the projectile at least 288 ft off the ground?

3 sec or 6 sec.

Explanation:

Given that, from the ground level a projectile is fired.

The equation which is given after t sec is,

The height of the projectile is given after t seconds is,

Now put this value in height equation will get.

Therefore the value of t will be 3 sec or 6 sec when projectile is at least 288 ft off from the ground.

there are no contact forces mentioned on the list of choices that you've provided.