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A particle is in free fall close to the Earth’s surface. Let O be a fixed point on the ground that lies away from the vertical line through the particle. Which of the following statements is incorrect?

1. The particle’s angular momentum about O is increasing in magnitude
2. The magnitude of the torque due to gravity about O is decreasing
3. The particle’s moment of inertia about O is decreasing
4. The magnitude of the particle’s angular velocity about O is increasing

Correct answer: The magnitude of the torque due to gravity about O is decreasing

Solution

The torque due to gravity about point O depends on the perpendicular distance from O to the line of action of the gravitational force. As the particle falls, this distance decreases, leading to a reduction in the magnitude of the torque.

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