1.

A child is standing with folded hands at the center of a platform rotating about its central axis. The kinetic energy of the system is `K`. The child now strectches his arms so that the moment of inertia of the system doubles. The kinetic energy of the system now is.A. 2 KB. `K//2`C. `K//4`D. 4 K

Answer» Correct Answer - B
From conservation of angular momentum `(I omega = constant)`, angular velocity will remain half.
As, `K = (L^(2))/(2 I)`
The rotational kinetic energy will become half. Hence, the correct option `(B)`.


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