Leaning Ladder
A figure climbs a ladder leaning against a block, demonstrating that mass *distribution* — not total mass — determines stability. The system is stable with the figure at the bottom …
Applications of Newton's Laws Topic
Spool with Ribbon
Demonstrates the counter-intuitive nature of torque. Depending on the angle of the ribbon, the spool rolls toward the pull, away from it, or slides without rotating. The critical angle where …
Weighted Disk
Demonstrates how a non-uniform mass distribution affects rolling motion. On a level surface, the disk always rolls back to place its center of mass at the lowest point. On an …
Friction Surfaces
Rubbing two metal blocks together produces a grating sound, making audible the microscopic surface interactions that cause friction. Students hear direct evidence that friction converts mechanical energy into sound and …
Sliding Blocks
Demonstrates that friction force is independent of contact area. Blocks pulled in series (large contact area) and stacked (small contact area) require the same force on the spring scale, directly …
Lifting Weights with Paper
Interleaved index cards and a folded paper loop demonstrate that friction scales with the number of contact surfaces and with perpendicular applied forces. Doubling the number of overlapping card sections …
