To solve this problem we will apply the concepts related to electric potential and electric potential energy. By definition we know that the electric potential is determined under the function:
= Coulomb's constant
q = Charge
r = Radius
At the same time
The values of variables are the same, then if we replace in a single equation we have this expression,
If we replace the values, we have finally that the charge is,
Therefore the potential energy of the system is 
Cleats Chicks Bits and Bollards. Hope this helps
Answer:
x=1.25m
Explanation:
The <em>Center of mass </em>of the system is defined as the point where whole mass of the body is appeared to be concentrated.
The center of mass of the system is given by
x= 
where m1 is mass of man =60 kg
m2 mass of board =20 kg
let the man be at the origin x1 =0 , x2 =5m
by substituting in above formula
x =
= 
=1.25 m
x=1.25m
So the center of mass of the system is at 1.25 m from man.
The answer I had got was C x
