Rotational MotionMedium
Question
A boy stands over the centre of a horizontal platform which is rotating freely with a speed of 2 revolution/s about a vertical axis through the centre of the platform and straight up through the boy. He holds 2 kg masses in each of his hands close to his body. The combined moment of inertia of the system is 1 kg-m2. The boy now stretches his arms so as to hold the masses far from his body. In this situation the moment of inertia of the system increases to 2 kg-m2. The kinetic energy of the system in the latter case as compared with that in the previous case will-
Options
A.Remain unchanged
B.Decrease
C.Increase
D.Remain uncertain
Solution
As he stretches hand, the MI increases so ω decreases and KE
=
= KE↓ (∴ I↑)
=
= KE↓ (∴ I↑)Create a free account to view solution
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