Coulomb's Law

Definition

Coulomb's Law states that the force between two charged objects is directly proportional to their charges and inversely proportional to the square of their distance apart.

Analogy

Imagine two magnets pulling towards each other. The stronger the magnets (charges) are, and the closer they are together, the greater their attraction will be.

Key Equations

• (F) is the force between charges,
• (q_1) and (q_2) are the magnitudes of the charges,
• (r) is the distance between the centers of the two charges,
• (k) is Coulomb's constant ((8.987 \times 10^9 , \text{Nm}^2/\text{C}^2)).

Problem Solving Tips

• Always express charges in Coulombs and distances in meters to maintain consistency with the unit system.
• Remember that forces are vectors. When multiple charges are involved, vector addition may be needed to find the net force.
• Pay attention to the signs of the charges; like charges repel, and unlike charges attract.

Relevant Experiments

• Measuring the force between charged objects at varying distances gives empirical evidence supporting (F \propto 1/r^2).
• Using charge sensors and force meters, one can quantify the relationship between charge magnitude, distance, and force, confirming Coulomb's Law.
• Experiments using a torsion balance are classic methods to demonstrate Coulomb’s Law, similar to how Coulomb originally explored the law.

Related terms

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