Physics

Problem

The torque

\tau

on a body about a given point is found to be equal to

\mathbf{A} \times \mathbf{L}

where

\mathbf{A}

is a constant vector, and

\mathbf{L}

is the angular momentum of the body about that point. From this it follows that a.

\frac{d\mathbf{L}}{dt}

is perpendicular to

\mathbf{L}

at all instants of time. b. the component of

\mathbf{L}

in the direction of

\mathbf{A}

does not change with time. c. the magnitude of

\mathbf{L}

does not change with time. d.

\mathbf{L}

does not change with time