Question 470: Centre of Mass and Rotational Motion

Question

An massless equilateral triangle EFG of side ‘a’ (As shown in figure) has three particles of mass m
situated at its vertices. The moment of inertia of the system about the line EX perpendicular to EG
in the plane of EFG is $${N \over {20}}$$ ma2
 where N is an integer. The value of N is _____.

Accepted Answer

I = m$$a$$
2
+ $${{m{a^2}} \over 4}$$ = $${5 \over 4}m{a^2}$$
Accoeding to the question,
$${5 \over 4}m{a^2} = {N \over {20}}m{a^2}$$
$$ \Rightarrow $$ N = 25

Centre of Mass and Rotational Motion

An massless equilateral triangle EFG of side ‘a’ (As shown in figure) has three particles of mass m situated at its vertices. The moment of inertia of the system about the line EX perpendicular to EG in the plane of EFG is ${N \over {20}}$ ma2 where N is an integer. The value of N is _____.

Choose the correct answer: