University Physics Supplementary Handout 1: Coulomb’s force

Consider the following point-like charges (charges that do not have structure (i.e zero size. Three charges 1 C, 2 C and -3 C are situated at the corners of a right triangle as shown. Find the net force on 1 C charge.

We first need to compute the magnitude of the forces F₂, and F_-3. Distance needed for F_-3 can be obtained from definition of sine,

opposite side = 10xSin (30) =10 (0.5) = 5 m

The total force is not 1.8x10⁺⁸+10.8x10⁺⁸ N. Because these forces are not in the same direction. We will find the total force by performing vector addition of F₂ and F_-3.