Centripetal Force — CalculationMediumQuestion 30654
Question
An electron (m = 9.1×10⁻³¹ kg) moves in a circle of radius 0.53×10⁻¹⁰ m at speed 2.2×10⁶ m/s. Centripetal force:
- A9.1×10⁻⁸ N
- B8.2×10⁻⁸ NCorrect
- C8.3×10⁻⁸ N
- D4.1×10⁻⁸ N
Correct answer
8.2×10⁻⁸ N
Explanation
F = mv²/r = 9.1×10⁻³¹ × (2.2×10⁶)² / (0.53×10⁻¹⁰) = 9.1×10⁻³¹ × 4.84×10¹² / 0.53×10⁻¹⁰ ≈ 8.3×10⁻⁸ N ≈ 8.2×10⁻⁸ N.