Formula Solid Cylinder / Rod (Rotation Perpendicular to Symmetry Axis) Moment of inertia Mass Length
$$I ~=~ \frac{1}{12} \, m \, l^2$$ $$I ~=~ \frac{1}{12} \, m \, l^2$$
Moment of inertia
$$ \class{brown}{I} $$ Unit $$ \mathrm{kg} \, \mathrm{m}^2 $$ According to \( M ~=~ I \, \alpha \) (\(\alpha\): angular acceleration), the moment of inertia determines how hard it is to generate a torque \(M\) on the body. Moment of inertia \(I\) depends on the mass distribution and on the choice of the axis of rotation. Here we calculate the moment of inertia of a solid cylinder whose axis of rotation is parallel to the diameter (perpendicular to the axis of symmetry).
Mass
$$ m $$ Unit $$ \mathrm{kg} $$ Total mass of the filled cylinder that is homogeneously distributed in the cylinder. The larger the mass, the larger the moment of inertia.
Length
$$ l $$ Unit $$ \mathrm{m} $$ Length of the cylinder. When the length is doubled, the moment of inertia is quadrupled.