Question

The function `h(t)=-16t^2+80t` represents the height of the baseball over time. How long do you think the ball will be in the air?

Answer 1

`5` time units.

Explanation:

This is not a calculus question!

`h(t) = 0` at ground level

`h(t) = 0 => -16t^2+80t=0`
`:. 16t^2 - 80t=0`
`:. 16t(1-5)=0`
`t=0`, or `t=5`

Interpretation
`t=0` represents the time at which the baseball first left the ground
`t=5` represents the time at which the baseball returns to the ground

So the ball is in the air for `5` time units.