Superposition of Forces
Drag a test charge among 4 fixed charges — net force = vector sum of individual forces.
Key Notes
The net force on a charge from many charges is the vector sum of individual Coulomb forces.
Forces add as vectors — magnitudes can never just be added unless all forces are colinear.
Each pairwise force is independent of all other charges in the system.
Used to compute fields from charge distributions: dE = k dq / r² and integrate.
Formulas
Superposition
Net force on a test charge q₀.
Resultant
Use components, then combine.
Important Points
Always resolve forces along axes before summing.
Symmetric configurations often cancel components — exploit symmetry first.
Continuous distributions: replace Σ with ∫ over dq.
Superposition of Forces notes from sciphylab (also known as SciPhy, SciPhy Lab, SciPhy Labs, Physics Lab). Class 12 physics revision for JEE Mains, JEE Advanced, NEET UG, AP Physics 1/2/C, SAT, and CUET-UG.