Question
A solid sphere is rotating freely about its symmetry axis in free space. The radius of the sphere is increased keeping its mass same. Which of the following physical quantities would remain constant for the sphere $?$
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Answer
As there is no external torque acting on a sphere,i.e,.${\tau _{ex}} = 0$
$So,\,\frac{{dL}}{{dt}} = {\tau _{ex}} = 0\,i.e.,\,L = $ constant
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