Question Detail
Question
In uniform circular motion of a particle, why is the angular momentum of the particle about the center of the circle constant?
Correct Answer
Option D is the correct answer.
Detailed Explanation
In uniform circular motion, the net force (centripetal force) is directed radially inward toward the center. The torque due to a force is τ = r × F. Since r (from the center to the particle) and F (toward the center) are parallel (or anti-parallel), their cross product is zero. With zero net torque, dL/dt = 0, so angular momentum L is constant.
Hint
Torque depends on both the force and the point about which it is calculated. Consider the direction of the force relative to the position vector from the center.