Learning objectives
- Identify six simple machines and their useful motions.
- Calculate ideal advantage from geometry.
- Connect lower effort to greater input travel.
- Explain efficiency and energy losses.
Key concepts
Load force = mg. Actual MA = load force ÷ effort force = η × IMA. Useful lifting work = load force × rise. No machine creates energy.
The lever uses a small rotation (maximum sine of angle 0.2). Effort and load forces are vertical. The pulley has 1, 2 or 4 supporting sections; moving rope markers show input travel.
The wheel winds a thin rope onto a constant-radius axle. The wedge is a single ramp lifting a guided block, not a cutting/fracture model. The screw is single-start, so pitch equals lead; drawn thread spacing is enlarged for visibility.
Efficiency is a lumped loss model, not a prediction of a particular friction coefficient. The external operator supplies the required effort throughout a slow lift.