weight is vector vary from place to place
 
        
                    
             
        
        
        
T² caries directly as R³ .
This is Kepler's 3rd law of planetary motion .
        
             
        
        
        
Answer:
W = 0 :The work done on the wall is zero,because the wall is not moving
Explanation:
Work theory
Work is the product of a force applied to a body and the displacement of the body in the direction of this force.
W= F*d Formula (1)
W: Work (Joules) (J)
F: force applied (N)
d=displacement of the body (m)
The work is positive (W+) if the force goes in the same direction of movement.
The work is negative (W-)if the force goes in the opposite direction to the movement
Data
F= 400-N
d= 0
Problem development
We apply formula (1) to calculate the work done on the wall:
W= 400*0
W=0
 
        
             
        
        
        
Answer:
The center of mass of the Earth–Moon system is 4.613 × 10⁶ m from center of the Earth.
Explanation:
Let the reference point be the center of the Earth

Where;
Xcm is the distance from center of the Earth =?
Me is the mass of the Earth = 6 × 10²⁴ kg
Xe is the center mass of the Earth = 0
Mm is the mass of the moon = 7 × 10²² kg
Xm is the center mass of the moon =  4 × 10⁸ m

Therefore, the center of mass of the Earth–Moon system is 4.613 × 10⁶ m from center of the Earth.