Placing a negative charge in the field of positive charge - Physics Stack Exchange most recent 30 from physics.stackexchange.com 2019-06-19T03:40:31Z https://physics.stackexchange.com/feeds/question/427981 http://www.creativecommons.org/licenses/by-sa/3.0/rdf https://physics.stackexchange.com/q/427981 0 Placing a negative charge in the field of positive charge Ahmad Eldesokey https://physics.stackexchange.com/users/206186 2018-09-10T23:32:19Z 2018-09-11T11:23:50Z <p>If we put a negative charge in the field of a positive charge and I know that the two charges attract each other, will the two charges attract each other until they touch? </p> https://physics.stackexchange.com/questions/427981/-/428065#428065 1 Answer by Costantino for Placing a negative charge in the field of positive charge Costantino https://physics.stackexchange.com/users/204754 2018-09-11T11:23:50Z 2018-09-11T11:23:50Z <p>If the system is isolated at what you described, yes: the two particles will be attracted by the Coulomb force </p> <p>$\vec{F_{Coul}} = k_e\cdot \frac{q_{neg}\cdot q_{pos}}{r^2}\cdot\vec{u_{r}} = \frac{d(m\vec{v})}{dt}$ </p> <p>with r the distance between the two particles and $\vec{u_r}$ the versor of the line that joins the two particles.</p> <p>So they will move with velocity $\vec{v}$ towards each other (obviously, the motion is computed for each of them separately).</p> <p>When they touch, however, depending of the nature of the particles there can be some energetic exchange, impact, or chemical bonding... Surely there would be a repelling force between the nuclei of the atoms once they reach the boundary distance.</p>