- #1

PFuser1232

- 479

- 20

$$\vec{r_{cm}} = \frac{\sum_{i=1}^n m_i \vec{r_i}}{\sum_{i=1}^n m_i}$$

Why is there no such thing as "centre of charge", defined for ##n## point charges:

$$\vec{r_{cq}} = \frac{\sum_{i=1}^n q_i \vec{r_i}}{\sum_{i=1}^n q_i}$$