Less force. More rope.: sources & model

Rerig a dock crane. Pull the same length of rope, watch the crate rise, and see what you trade for an easier lift.

What supports the explanation?

What this model assumes

1. Two authored rope routes with ideal massless, inextensible rope; the rigging cannot be arbitrarily rearranged.
2. Motion is prescribed slowly. Acceleration, rope stretch, pulley friction and crane stability are not simulated.
3. The lever readout is horizontal static balance. Its inspection animation does not calculate dynamic lever forces.
4. Count supporting segments: For a massless rope and frictionless wheels, the same tension T acts along the rope. With n vertical supporting segments, nT=mg. The crate and moving hardware are represented by the selected combined mass.
5. Travel pays for force: If the load rises h, all n supporting segments shorten by h, so the free end moves s=nh. Ideal input work Ts equals output work mgh. The crane reports force, rise and work together.
6. Balance turning effects: For the horizontal lever, effort force × perpendicular effort arm = load weight × perpendicular load arm. Real pulleys have friction; real levers have weight and bending. Those losses are absent here.

What has been checked

Analytical reference cases, conservation or transition invariants, finite drawing commands, bounded setup parsing, discovery and route integrity are checked automatically. These checks do not establish anatomical fidelity, learner outcomes or browser/device compatibility. Independent subject review, learner trials, comprehensive accessibility review and browser video encoding checks remain pending.

Each source supports the associated claim. Sources do not certify this implementation or its visuals.

About the cover illustration

The topic card uses an AI-generated editorial illustration. It introduces the subject; it is not a validated anatomical reference or a measured landscape. The experiment’s diagrams, readouts and assumptions explain the model separately.