An incline is a useful, simple device. In other words, it is a simple machine. Lifting a ball consumes more energy than rolling it up an incline does. This is why inclines are useful in many situations, for example when moving barrels and other round containers. 

Stairs are an example of an incline. When climbing to the roof with ladders, the distance is shorter but the amount of energy consumed is larger. This is why stairs are useful: although they take up more space than ladders, they require less energy and effort from the person climbing them. 


Image on the left: Rolling a ball up an incline saves energy. Image on the right: Stairs are an example of an incline. 

A serpentine or switchback road is also a good example of an incline. A road that climbs the hill in a straight line would be too steep and require too much energy and effort. That is why a road that crosses from one side to the other is more useful. The road is longer than straight road, but it requires less energy and effort to climb. 

Inclines are also used in funniculars. Lifting a group of people on the top of a steep hill takes more energy than lifting them along an incline. 


Image on the left: A serpentine road is an example of an incline. This picture is from the Italian Alps. Image on the right: A funnicular is an example of an incline. This picture is from Portugal.