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:
“Let us hope ... that by the best cultivation of the physical world, beneath and around us; and the intellectual and moral world within us, we shall secure an individual, social and political prosperity and happiness, whose course shall be onward and upward, and which, while the earth endures, shall not pass away.”
—Abraham Lincoln (1809–1865)
“In America the majority raises formidable barriers around the liberty of opinion; within these barriers an author may write what he pleases, but woe to him if he goes beyond them.”
—Alexis de Tocqueville (1805–1859)