The Power of Equilibrium: Finding Balance in Electrostatics

Understanding the concept of equilibrium in electrostatics can lead us to new heights, quite literally in this case. By balancing the forces acting on the small sphere of mass 'm' and charge 'q', we can find the perfect spot for it to remain still within the insulating cylinder.

When looking at the forces at play, we have the gravitational force pulling the sphere downward with a strength of mg, where m is the mass of the sphere and g is the acceleration due to gravity. On the other hand, the electrostatic force between the two charges, represented by Coulomb's law, pushes back with a force of q1*q2 / (4πε0r²), where q1 and q2 are the charges, r is the distance between the charges, and ε0 is the permittivity of free space.

For the sphere to be at equilibrium, these forces need to balance out. By setting mg equal to q1*q2 / (4πε0r²) and considering that one of the charges is fixed at the bottom of the cylinder, we can replace 'r' with the height 'h'. The formula h = q^2 / (4πε0mg) emerges as the key to finding that perfect height where the sphere remains still, in complete balance.

Through understanding the delicate interplay of forces in electrostatics, we can discover the beauty of equilibrium and the power it holds in keeping objects stable in seemingly precarious positions.