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F = ma (Final Problems)
Dynamics
FMA-2025-24 · 2025 F = ma (AAPT)

2025 F = ma Exam — Question 24

A massive bead is attached to the end of a massless rigid rod of length L. The other end of the rod is attached to an ideal pivot, which allows it to rotate frictionlessly in any direction. The rod is initially at angle θ to the horizontal, and there is no gravitational force. θ Next, the bead receives an impulse directly into the page, giving it a speed v. How long does it take for the bead to return to its original position?
Source: Question 24, 2025 F = ma Exam, © 2025 American Association of Physics Teachers (AAPT) and the U.S. Physics Team. Adapted by PhysicsTrainer: reformatted into a separate question and answer choices for online multiple-choice practice; any shared setup from nearby questions is repeated here. Not affiliated with or endorsed by AAPT or the U.S. Physics Team.