Exam-style question
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A rotating disk has an initial angular momentum of 10 kg·m²/s. If no external torque acts on it, what will its angular momentum be after 5 seconds?.
- A.10 kg·m²/s
- B.5 kg·m²/s
- C.0 kg·m²/s
- D.20 kg·m²/s
Model answer
What a good answer should say
- 10 kg·m²/s
Explanation
Why this works
The conservation of angular momentum states that in the absence of external torques, the angular momentum remains constant. Therefore, the angular momentum after 5 seconds will still be 10 kg·m²/s.
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