When a mass is rotating in a plane about a fixed point, its angular momentum is directed along

When a mass is rotating in a plane about a fixed point, its angular momentum is directed along
  1. a line perpendicular to the plane of rotation
  2. the line making an angle of $45^{\circ}$ to the plane of rotation
  3. the radius
  4. the tangent to the orbit

Solution

We knows $\mathbf{L}=m(\mathbf{r} \times \mathbf{v})$ So here, angular momentum is directed along a line perpendicular to the plane of rotation.

Asked in: NEET 2012 (Screening)

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