precession (conceptual)

Question

A sπnning top precesses due to torque from?

RankGuru · Accepted Answer

1. **Tipping Torque**: Consider a spinning top tilted at an angle. The force of gravity ($Mg$) acts at the Center of Mass (COM), and the normal reaction ($N$) acts at the tip.
2. **Couple**: These two parallel and opposite forces create a torque $\vec{	au} = \vec{R}_{cm} 	imes \vec{F}_g$.
3. **Angular Momentum Response**: The torque is perpendicular to the angular momentum ($\uvec{L}$) of the top. Instead of falling, $\uvec{L}$ changes its horizontal orientation.
4. **Effect**: The axis of the top traces a cone around the vertical. This motion is called **precession**.

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precession (conceptual)

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