Question

A uniform metallic rod rotates about its perpendicular bisector with constant angular speed. If it is heated uniformly to raise its temperature slightly:

• A. its speed of rotation increases
• B. its speed of rotation decreases
• C. its speed of rotation remains same
• D. its speed increases because its moments of inertia increases

Answer 1

The correct option is B its speed of rotation decreases

When the rod is heated uniformly to raise its temperature slightly, the length of the rod will be increased due to heating. This leads to increase in its moment of inertia $\left(I\right)$.

Since angular momentum,$L=I\omega$

To maintain the angular momentum conserved, $\omega$(angular speed ) decreases with an increase in moment of inertia.