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F = ma (Final Problems)
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FMA-2026-22 · 2026 F = ma (AAPT)

2026 F = ma Exam — Question 22

A tricycle of mass m = 100 kg is traveling north on a horizontal surface. The geometry of the tricycle is defined as follows: • Wheelbase (distance from front axle to rear axle): L = 1.0 m • Rear track width (distance between rear wheels): d = 1.0 m • Center of mass (CM) location: on the longitudinal symmetry axis, a distance b = 0.4 m forward of the rear axle • Radius of gyration about the CM: k = 0.5 m (The radius of gyration k is defined by ICM = mk 2 , where ICM is the moment of inertia of the tricycle about a vertical axis through its center of mass.) Seeing a patch of ice on their right side ahead, the rider panics and slams on the brakes. The front wheel and the left rear wheel slide on dry pavement with a coefficient of kinetic friction µk = 0.5, while the right rear wheel slides on frictionless ice (µ = 0). This asymmetry in friction forces produces a net torque about the center of mass, causing the tricycle to begin rotating. Calculate the initial angular acceleration α of the tricycle.
Source: Question 22, 2026 F = ma Exam, © 2026 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.