Practice question · True or false
Coulomb's law and Newton's gravitation share the inverse-square form, but only one of the two forces can repel.
Hints
- How many signs of charge are there? How many of mass?
- Gravity has one sign; charge has two.
Show the answer
True
Why
True. Charge comes in two signs, so the electric force attracts or repels; mass comes in one, so gravity only attracts. That is why gravity dominates at astronomical scale despite being vastly weaker, bulk matter is electrically neutral, so the stronger force cancels itself out and the weaker one accumulates.
Practise Electromagnetism
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