# Problem on electrostatic force

1. Jan 20, 2015

### arpon

1. The problem statement, all variables and given/known data
A metal sphere of radius R and total charge Q is cut into two equal halves. Find the force that is
necessary to hold the two parts together.

2. Relevant equations
$F = \frac{1}{4\pi \epsilon _0} \cdot \frac {q_1 q_2}{r^2}$
$\oint \vec E \cdot d \vec A = \frac{q}{\epsilon _0}$

3. The attempt at a solution
Is there any other way which is easy to calculate rather than columb's law (using calculus)?

2. Jan 20, 2015

### Orodruin

Staff Emeritus
Have you tried computing the electromagnetic stress tensor from the field strength and integrating it over a "well chosen" surface?