Common angular velocity from angular momentum conversation
ω=I1+I2l1ω1+I2ω2=0.1+0.20.1×10+0.2×5=320
Final K.E.
Kf=21I1ω2+21I2ω2
=21(0.1+0.2)×(320)2⇒kf=320
Two uniform circular discs are rotating independently in the same direction around their common axis passing through their centres. The moment of…
JEE Main 2020 — Physics Mechanics
2020mcqmedium
Two uniform circular discs are rotating independently in the same direction around their common axis passing through their centres. The moment of inertia and angular velocity of the first disc are 0.1kg−m2 and 10 rad s−1 respectively while those for the second one are 0.2kg−m2and 5rads−1 respectively. At some instant they get stuck together and start rotating as a single system about their common axis with some angular speed. The kinetic energy of the combined system is :
Official previous-year question
Held on 2 Sept 2020 · Verified 6 Jul 2026.
Options
- A
310J
- B
320J
- C
35J
- D
32J
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