Exam-style question
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What is the rotational kinetic energy of an object with a moment of inertia of 4 kg·m² and an angular velocity of 3 rad/s?.
- A.18 J
- B.12 J
- C.36 J
- D.24 J
Model answer
What a good answer should say
- 18 J
Explanation
Why this works
The formula for rotational kinetic energy is Ek = 0.5 x I x ω². Substituting the values, Ek = 0.5 x 4 kg·m² x (3 rad/s)² = 0.5 x 4 x 9 = 18 J.
Thus, the rotational kinetic energy is 18 J.
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