When a mass is rotating in a plane about a fixed point, its angular momentum is directed along:
Correct answer: C. The line perpendicular to the plane of rotation
- A. The radius
- B. Tangent to the orbit
- C. The line perpendicular to the plane of rotation
- D. None of these
Explanation
Angular momentum (L) is a vector quantity defined as the cross product of the position vector (r) and linear momentum (p): L=r×p For a particle moving in a plane about a fixed point, the angular momentum is directed along the axis perpendicular to the plane of rotation, following the right-hand rule. This means that the angular momentum vector is perpendicular to both the position vector and the linear momentum vector. Therefore, option (c) "The line perpendicular to the plane of rotation" is correct.
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