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## Homework Statement

Two dust particles are separated by 0.01m and of the same mass and charge, find the total potential energy

## Homework Equations

[tex]E_{el}=k\frac{q_1 q_2}{r}[/tex]

[tex]E_{grav}=-G\frac{m_1 m_2}{r}[/tex]

[tex]r=0.01 m[/tex], [tex]q_1=q_2=1.1201\times10^{-18} C[/tex] [tex]m_1=m_2=13\times10^{-9} kg[/tex]

Where G and k are the gravitational and Coulomb's constant respectively.

## The Attempt at a Solution

[tex]E_{el}=1.128\times10^{-24} J[/tex]

[tex]E_{grav}=-1.128\times10^{-24} J[/tex]

Not sure whether it [tex]E_{tot}=E_{el}+E_{grav}[/tex] or [tex]E_{tot}=\left|E_{el}\right|+\left|E_{grav}\right|[/tex]?