AP EAPCET 06-Jul-2022 Shift 1 Paper

When uniform metallic rod is heated, which causes thermal expansion in length, so radius of gyration (K) increases, hence moment of inertia (I)=MK2 increases. So reason (R) is correct, but angular momentum remains conserved according to law of conservation of angular momentum because external torque, (τ)=0
So; L= constant =Iω
(before heating) I1ω1=I2ω2 (After heating)
⇒‌‌‌

ω2

ω1

=‌

I1

I2

Since, I2>I1
∴‌‌

ω2

ω1

<1
∴‌ω2<ω1
Hence, its angular speed decreases.