Question : A uniform metallic rod rotates about its perpendicular bisector with constant angular speed. If it is heated uniformly to raise its temperature slightly then
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 moment of inertia increases.
Doubt by Muskan
Solution : Coming Soon
When the temperature of the metallic rod is increased then due to phenomenon of thermal expansion its length will increase.
We know,
Moment of Inertia of the metallic rod which is rotating about its perpendicular bisector is given by
I = ML²/12
So when L increases then MI of the rod will also increases.
As per the law of conservation of Angular Momentum
L (Angular Momentum) = Iω = const.
I∝1/ω
So when moment of Inertia (I) will increases then Angular speed (ω) of the rod will decreases.
Hence, b) would be the correct option.