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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