Natural Sciences · Foundational · Lesson 5 of 7
No Free Lunch
Work and efficiency
An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.
What you’ll learn
- No machine outputs more work than goes in. Perpetual motion is impossible.
- Efficiency = work out ÷ work in = actual MA ÷ ideal MA.
- Friction makes real machines less than 100% efficient.
Steps
- Perpetual motion
- Efficiency
- Real pulley
- Machines in a chain
- Losses multiply
- Actual vs ideal