A. 1 dimensional coordinate system
Explanation:
The ball is in free fall (gravity is the only force acting on the ball), so its acceleration is 9.8 m/s² down during the entire path.
So, the force of gravity that the asteroid and the planet have on each other approximately 
<h3>Introduction</h3>
Hi ! Now, I will help to discuss about the gravitational force between two objects. The force of gravity is not affected by the radius of an object, but radius between two object. Moreover, if the object is a planet, the radius of the planet is only to calculate the "gravitational acceleration" on the planet itself,does not determine the gravitational force between the two planets. For the gravitational force between two objects, it can be calculated using the following formula :

With the following condition :
- F = gravitational force (N)
- G = gravity constant ≈
N.m²/kg²
= mass of the first object (kg)
= mass of the second object (kg)- r = distance between two objects (m)
<h3>Problem Solving</h3>
We know that :
- G = gravity constant ≈
N.m²/kg²
= mass of the planet X =
kg.
= mass of the planet Y =
kg.- r = distance between two objects =
m.
What was asked :
- F = gravitational force = ... N
Step by step :





<h3>Conclusion</h3>
So, the force of gravity that the asteroid and the planet have on each other approximately

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