Question

The torque acting on a body about a given point is given by $\tau = \overrightarrow{A} \times\overrightarrow{L}$ where $\overrightarrow {A}$ is a constant vector and $\overrightarrow {L}$ is the angular momentum of the body about this point. It follows that

• A. the magnitude of $\overrightarrow {L}$ does not change with time
• B. the component of $\overrightarrow {L}$ in the direction of $\overrightarrow {A}$ does not change with time
• C. $\frac {d\overrightarrow L} {dt}$ is perpendicular to $\overrightarrow {L}$ at all instants of time
• D. All of the above choices are correct

Answer 1

Answer: (D)

All of the above choices are correct

Answer 2

$\tau = A \times L$ $A =$ constant vector $L =$ angular momentum In $A$ and $L$ there will be no change. So. all the above choices are correct.