A platform is revolving in horizontal plane about a fixed axis and a boy is sitting at centre. The initial kinetic energy of system is K. If the boy stretches his arms then moment of inertia of system becomes double. Final kinetic energy of system is :
A
K
B
C
D
2K
Text Solution
Verified by ExpertsThe correct answer is:
B
From conservation of angular momentum ( Ιω = constant), angular velocity will remain half. As,
K = 
Ιω 2
The rotational kinetic energy will become half. Hence, the correct option is
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