The function is $\"\"$ .

Where $\"\"$ is the height at point $\"\"$ , $\"\"$ is height at point $\"\"$ , and $\"\"$ is the acceleration due to gravity.

When $\"\"$ is decreases to $\"\"$ .

Substitute $\"\"$ in $\"\"$ .

$\"\"$

As height $\"\"$ is decreases to $\"\"$ , the speed at point $\"\"$ approaches $\"\"$ .