Question 641: Centre of Mass and Rotational Motion

Question

Two rotating bodies A and B of masses m  and  2m with moments of inertia ${I_A}$ and ${I_B}$ (${I_B}$ > ${I_A}$) have equal kinetic energy of rotation. If L
A
and L
B
be their angular momenta respectively, then

Accepted Answer

It is known that rotational kinetic energy is
given as :
$E = {{I{\omega ^2}} \over 2}$ = ${{{L^2}} \over {2I}}$
Hence, L
2
$ \propto $ I
Further, E
A
= E
B
Also, ${{{L_A}^2} \over {2{I_A}}} = {{{L_B}^2} \over {2{I_B}}}$
${I_B} > {I_A}$
${L_B} > {L_A}$

Answer

${L_A} = {{{L_B}} \over 2}$

Answer

${L_A} = 2{L_B}$

Answer

${L_B} > {L_A}$

Answer

${L_A} > {L_B}$

Centre of Mass and Rotational Motion

Two rotating bodies A and B of masses m and 2m with moments of inertia {I_A} and {I_B} ({I_B} > {I_A}) have equal kinetic energy of rotation. If L A and L B be their angular momenta respectively, then

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