Lifting a Boulder With a Plank

A plank resting on a steel wedge lets a small push at one end raise a heavy boulder at the other end. The farther your hand is from the pivot, the less force you need.

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In the picture

The granite boulder: the load, resting on the short arm of the plank.
The short arm of the plank: the stretch between the load and the pivot; the shorter it is, the bigger the force delivered to the load.
The steel triangle: the pivot, the fixed point the plank turns around.
The long arm of the plank: the stretch between the pivot and the hand; a longer arm needs a smaller push.
The gloved hand: the effort pressing down, travelling a long way to raise the boulder a little.

Examples

A see-saw: a light child sitting far from the middle can lift a heavier friend sitting close to it.
A wheelbarrow: the wheel is the pivot, and the long handles lift a heavy load with a small pull.

Key takeaways

Force times distance from the pivot is equal on both sides, so a longer arm needs less force.
You trade distance for force: your hand moves far while the load rises only a little.