A certain freely falling object, released from rest, requires 1.50 s to travel the last 30.0 m before it hits the ground. From what height above the ground did it fall

The object fell from about 38.14 meters

Explanation:

We can use the formula for displacement under accelerated motion due to gravity to find the velocity of the object had 30 m before hitting the ground :

Now, knowing this velocity, we can find the time it took to fall from the initial position to 30 m before hitting the ground:

And now we can find what is the total distance covered in 1.5 s plus 1.29 seconds for this free falling object:

3. dark matter

empty space could also be a simple vacuum