A particle moves with constant velocity. At instant t = 0, the particle is at the position of minimum separation from fixed point P. Its angular momentum about P is L ( $\not \neq$ 0). Subsequently its angular momentum about point P
A) increases with time.
B) decreases with time.
C) does not change with time.
D) Hold it! A particle moving with constant velocity has no angular momentum.

Question

Quizplus · Accepted Answer

Angular momentum of a particle moving with constant velocity about a fixed point does not change with time. This is because angular momentum, $L = r \times p$ (where $r$ is the position vector from the point to the particle and $p$ is the linear momentum), remains constant if both the magnitude and direction of velocity (and hence momentum) are constant, as the perpendicular distance to the line of motion (which contributes to the magnitude of $r \times p$) does not change.

A Particle Moves with Constant Velocity ≠̸\not \neq= 0) Subsequently Its Angular Momentum About Point P A) Increases

A Particle Moves with Constant Velocity $\not \neq$ 0) Subsequently Its Angular Momentum About Point P
A) Increases