Inclined Plane

An inclined plane is a flat surface that tilts at an angle. It is one of the six simple machines that humans have used for thousands of years. A ramp is the most common example. So is a slide on a playground, a wheelchair ramp, or a road winding up the side of a hill.

An inclined plane makes work easier by trading distance for force. Lifting a heavy box straight up into a truck takes a lot of strength. Pushing that same box up a ramp takes less force, but you have to push it a longer way. The total work is about the same. Your muscles just spread it out over more distance.

The gentler the slope, the easier the push. A steep ramp needs more force. A long, low ramp needs less. That is why mountain roads zigzag back and forth instead of going straight up. Each switchback keeps the slope gentle enough for cars to climb.

Inclined planes are hiding all over the world. The ancient Egyptians probably used giant earth ramps to haul stones up the sides of the pyramids. A knife blade is a kind of moving inclined plane. So is a staircase, a funnel, and even the sloped bottom of a bathtub. Once you spot the shape, you start seeing it everywhere.