Answer: 80 kg·m²/s.
- A 80 kg·m²/s
- B 320 kg·m²/s
- C 5 kg·m²/s
- D 20 kg·m²/s
Correct answer: A. 80 kg·m²/s
Explanation: Angular impulse = τ × t = ΔL. L = 20 × 4 = 80 kg·m²/s (starting from rest).
Torque about axis O equals the force F multiplied by the perpendicular distance r⊥ from the axis to the line of action of the force, producing rotation.
Concept context
Moment of inertia, torque, angular momentum, rolling motion. Very high JEE weightage.
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