Physical Barriers
As physical obstacles, we can enumerate all those physical barriers that block the action and prevent the progress or the achievement of a concrete goal. Examples:
- architectural barriers that hinder access to people with reduced mobility;
- doors, gates, and access control systems, designed to keep intruders or attackers out;
- large objects, fallen trees or collapses through passageways, paths, roads, railroads, waterways or airfields, preventing mobility;
- sandbanks, rocks or coral reefs, preventing free navigation;
- hills, mountains and weather phenomena preventing the free traffic of aircraft;
- meteors, meteorites, micrometeorites, cosmic dust, comets, space debris, strong electromagnetic radiation or gravitational field, preventing a spacecraft from navigating freely in space.
Read more about this topic: Obstacle
Famous quotes containing the words physical and/or barriers:
“The struggle for existence holds as much in the intellectual as in the physical world. A theory is a species of thinking, and its right to exist is coextensive with its power of resisting extinction by its rivals.”
—Thomas Henry Huxley (1825–95)
“There are two barriers that often prevent communication between the young and their elders. The first is middle-aged forgetfulness of the fact that they themselves are no longer young. The second is youthful ignorance of the fact that the middle aged are still alive.”
—Jessamyn West (1902–1984)