This how it works covers Why Levers Multiply Force: The Deep Physics within Moments & Levers for GCSE Physics. Revise Moments & Levers in Forces for GCSE Physics with 13 exam-style questions and 10 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 7 of 14 in this topic. Use this how it works to connect the idea to the wider topic before moving on to questions and flashcards.
⚙️ Why Levers Multiply Force: The Deep Physics
A lever does not create energy — it trades force for distance. When you apply a small effort force over a large distance, the load moves a small distance but experiences a much larger force. This is consistent with the conservation of energy: work input (effort × effort distance) = work output (load × load distance), ignoring friction.
The pivot position determines the mechanical advantage. Moving the pivot closer to the load increases the mechanical advantage — a smaller effort lifts a larger load. This is why a wheelbarrow has the wheel (pivot) near the load — you can lift a heavy weight with relatively little effort.
Gears work on the same principle: the ratio of gear teeth determines the ratio of forces (torques). A gear with 40 teeth meshing with a gear with 10 teeth produces 4× the torque — but rotates at 1/4 the speed.
Practice questions for Moments & Levers
What is a moment?
State the principle of moments.