Distance is a scalar and measured only by units (meters, feet). Position is a vector and depends on where the origin is. It can be negative or positive and has direction.
F~1/r²
doubling the distance r, Decreases the force by ¼
<h2>
Answer:53.63
</h2>
Explanation:
The equations of motion used in this question is 
When a object is projected horizontally from a sufficiently height,the x-component of acceleration remains zero because there is no force that drags the object in x direction.
But,due to gravity,the object accelerates downward at a rate of
.
In X-Direction,
Given that initial velocity=
=
Using
,

In Y-Direction,
Given that initial velocity=
=
Using
,



Send wave from your location to the object and wait until echo is back.
Measure the time taken.
If you know the speed of wave (say sound wave), than just multiply by half time taken wave to return