Exam-style question
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If a solid cylinder has a moment of inertia of 0.4 kg·m² and is rotating with an angular velocity of 10 rad/s, what is its rotational kinetic energy?.
- A.20 J
- B.40 J
- C.60 J
- D.80 J
Model answer
What a good answer should say
- 20 J
Explanation
Why this works
The formula for rotational kinetic energy is KE = 0.5 * I * ω². Substituting the values, KE = 0.5 * 0.4 kg·m² * (10 rad/s)² = 0.5 * 0.4 * 100 = 20 J.
Therefore, the rotational kinetic energy is 20 J.
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