Rotational Inertia Comparator – AP Physics 1

Learning Objectives

Compare rotational inertia of different shapes

Understand I = ΣmᵢRᵢ² and shape-specific formulas

Predict which object wins a ramp race

Apply rolling without slipping: v = ωR

Key Insight

Objects with lower I/(mR²) roll faster down a ramp because less energy goes into rotation and more into translation. A solid sphere beats a hollow sphere beats a solid cylinder!