Concept:An inclined plane is a sloping surface that reduces the force needed to move an object up or down by increasing the distance travelled.
Explanation:A path of a hill is a natural example of an inclined plane. Instead of climbing straight up, the slope allows a person or vehicle to move gradually upward with less effort.
The slope spreads the vertical rise over a longer horizontal distance, so less force is required to overcome gravity.
A flat road surface is not an inclined plane because it has no slope or change in elevation, so it cannot multiply force.
A see-saw is a lever, which uses a fulcrum or pivot point to help lift or balance loads.
A pulley consists of a grooved wheel and a rope and is used mainly to change the direction of a lifting force.
Therefore, among the given options, only the path of a hill matches the definition of an inclined plane.
Answer:D. path of a hill.
