This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: For two stationary point particles, with charges 1 q and 2 q , separated by a distance r , the magnitude of the electrostatic force exerted by one particle onto the other is 2 2 1 1 2 2 1 r q q k F F = = ← ← . The constant k in Coulomb’s law is called the electrostatic constant. The units of k are = ] [ k Nm 2 /C 2 , and 9 10 99 . 8 × = k Nm 2 /C 2 . We will often use the approximation 9 10 . 9 × ≈ k Nm 2 /C 2 . Often Coulomb’s law is written in terms of the permittivity constant, 12 10 85 . 8 − × = ε C 2 /(Nm 2 ), rather than in term of k . These two constants are related by 4 1 πε = k . The electrostatic force obeys the principle of superposition. For n stationary charged point particles: n F F F F ← ← ← ← + + + = 1 3 1 2 1 all 1 L . Note that this is a vector sum. Force directions: 1 > q 2 > q 1 > q 2 < q 1 < q 2 < q 2 1 ← F r 2 1 ← F r 2 1 ← F r 1 2 ← F r 1 2 ← F r 1 2 ← F r...
View
Full Document
 Spring '07
 FULBRIGHT, R
 Physics, Charge, Electric charge

Click to edit the document details