The answer is C. Hope this helps.
As we know that electrostatic force between two charges is given as

here we know that electrostatic repulsion force is balanced by the gravitational force between them
so here force of attraction due to gravitation is given as

here we can assume that both will have equal charge of magnitude "q"
now we have



now we have

Answer:
F' = 64 F
Explanation:
The electric force between charges is given by :

Where
q₁ and q₂ are charges
r is the distance between charges
When each charge is doubled and the distance between them is 1/4 its original magnitude such that,
q₁' = 2q₁, q₂' = 2q₂ and r' = (r/4)
New force,

Apply new values,

So, the new force becomes 64 times the initial force.
<span>AS T1,T2,T3 are the tensions in the ropes,assuming that there are Three blocks of mass 3m, 2m, and m.T3 is the string between 3m and 2m,T2 is the string between 2m and m ,T1 is the string attached to m thus T1 pulls the whole set of blocks along, so it must be the largest. T2 pulls the last
two masses, but T3 only pulls the last mass, so T3 < T2 < T1.</span>
Answer:
3.125J
Explanation:
K.E.= 1/2(mass)(velocity)^2
K.E.=1/2(0.25)(5)^2=3.125