lesson
A mechanism can change the job
1 · Learn
A lever turns about a pivot. With a suitable arrangement, a small force acting farther from the pivot can move a larger load nearer it. A pulley can change the direction of a pull; some pulley arrangements reduce the force needed.
Gears transfer rotation. Meshing gears turn in opposite directions, and their sizes affect turns and speed. Mechanisms do not create energy for free: reducing force usually involves moving farther.
2 · Worked example
I use a safe model lever to compare positions while keeping the load the same. I describe the arrangement rather than claiming every lever always reduces effort.
3 · Your turn
Does every single fixed pulley automatically halve the force needed? What can it change?
Check your answer
No. A simple fixed pulley mainly changes the direction of the pull. Mechanical advantage depends on the full arrangement.
4 · Apply your learning
Investigate adult-approved model levers or gears with small safe loads. Label parts and explain a pattern supported by the observations.
Adult guidance and safety
No heavy lifting, pinching gear systems, climbing or load-bearing homemade devices. Adults supervise safe classroom models.
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Check a calculation · Year 5 onward
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