Question

Find the rotational inertia of 21.5 kilograms thin-walled cylindrical threshing drum of a modified palay thresher having a radius of 9 inches.

Answer 1

Explanation & Calculation

• The rotational inertia of a thin-walled cylinder about its major axis is given by the same formula that is used for a ring and so on,

$\qquad\qquad \begin{aligned} \small I&=\small mr^2 \end{aligned}$

• Here, the mass is given and all you need is to get the reading for the radius converted into meters prior to input in the formula.

$\qquad\qquad \begin{aligned} \small 1\,in&=\small 2.54\,cm=2.54\times10^{-2}\,m \end{aligned}$

• Now you can calculate the answer.