A small bead slides without friction on a circular hoop of radius ( R ). The hoop rotates about its vertical diameter with constant angular velocity ( \omega ). Find the equilibrium positions of the bead relative to the hoop and determine their stability.
In Problem 3, what happens if the hoop is also oscillating vertically? (You are now ready for the IPhO.) If you enjoyed this article, download the full PDF containing 50 additional mechanics problems with step-by-step video-linked solutions. A small bead slides without friction on a
The constraint ( a_2 + a_3 = a_1 ) is non-negotiable. Most mistakes come from forgetting that ( P_2 ) moves. Problem 3: The Rotating Hoop (Effective Potential) Difficulty: ⭐⭐⭐⭐⭐ In Problem 3, what happens if the hoop
[ a_1 = g \cdot \frac{4m - m_1}{4m + m_1}, \quad a_2 = -a_3 = g \cdot \frac{m_1}{4m + m_1} ] Most mistakes come from forgetting that ( P_2 ) moves
( \frac{dU_{eff}}{d\theta} = 0 ) [ mgR \sin\theta - m\omega^2 R^2 \sin\theta \cos\theta = 0 ] [ mR \sin\theta ( g - \omega^2 R \cos\theta ) = 0 ]
The problems above are archetypes. Solve them until the method becomes reflexive. Then modify them: add friction, change the geometry, add a spring. That is the difference between a contestant and a champion.