Question

5. Three charges with q = 7.5 x 10-6 C are located as shown, where

L = 25 cm. Determine the total electric force on the circled particle.

Answer 1

F12 = k • q1 • q2 / r12²

F12 = (9 × 10⁹) • (7.5 × 10⁻⁶)² / (0.25)²

F12 = 8.1 N

F13 = k • q1 • q2 / r12²

F12 = (9 × 10⁹) • (7.5 × 10⁻⁶)² / (0.25² + 0.25²)

F12 = 4.05 N

F² = F12² + F13² + 2(F12)(F13) cos θ

F² = (8.1)² + (4.05)² + 2(8.1)(4.05) cos 45°

F = 11.33 N