<h2>
Answer:</h2>
The time taken by football to hit the ground is:
t=2.3561 sec.
<h2>
Step-by-step explanation:</h2>
The height(h) of the football at a time t is given by the equation:

Now, we are asked to find the time the ball will take to hit the ground.
i.e. we are asked to find the value of t when h=0
i.e.

( Since, on multiplying both the sides of the equation by -1 )
Now, we divide both the side of the equation by 4 to get:

We know that the solution of the quadratic equation of the type:

is given by the formula:

Here we have:

Hence, the solution is:

Also, we know that:

This means that:

time can't be negative.
Hence, the solution is: 