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A sphere of radius r has surface area 4πr 2.. The surface area (symbol A) of a solid object is a measure of the total area that the surface of the object occupies. [1] The mathematical definition of surface area in the presence of curved surfaces is considerably more involved than the definition of arc length of one-dimensional curves, or of the surface area for polyhedra (i.e., objects with ...
Scratches, represented by triangular-shaped grooves, make the surface area greater. Specific surface area (SSA) is a property of solids defined as the total surface area (SA) of a material per unit mass, [1] (with units of m 2 /kg or m 2 /g). Alternatively, it may be defined as SA per solid or bulk volume [2] [3] (units of m 2 /m 3 or m −1).
The formula for the surface area of a sphere is more difficult to derive: because a sphere has nonzero Gaussian curvature, it cannot be flattened out. The formula for the surface area of a sphere was first obtained by Archimedes in his work On the Sphere and Cylinder. The formula is: [6] A = 4πr 2 (sphere), where r is the radius of the sphere.
A unit of area traditionally defined as the area of a plot of land one chain (66 feet) by one furlong (660 feet), equivalent to 43,560 square feet (0.001563 sq mi; 4,047 m 2), or about 0.40 hectare. active volcano A volcano that is currently erupting, or one that has erupted within the last 10,000 years (the Holocene) or during recorded history ...
Also narrow. A land or water passage that is confined or restricted by its narrow breadth, often a strait or a water gap. nation A stable community of people formed on the basis of a common geographic territory, language, economy, ethnicity, or psychological make-up as manifested in a common culture. national mapping agency A governmental agency which manages, produces, and publishes ...
The ocean surface has globally little, but measurable topography, depending on the ocean's volumes. The ocean surface is a crucial interface for oceanic and atmospheric processes. Allowing interchange of particles, enriching the air and water, as well as grounds by some particles becoming sediments. This interchange has fertilized life in the ...
An approximation for the volume of a thin spherical shell is the surface area of the inner sphere multiplied by the thickness t of the shell: [2], when t is very small compared to r (). The total surface area of the spherical shell is .
the length of the organism, as the surface area of just the front 2/3 of the organism has an effect on the drag. The resistance to the motion of an approximately stream-lined solid through a fluid can be expressed by the formula: C fρ (total surface)V 2 /2, [19] where: V = velocity ρ = density of fluid C f = 1.33R − 1 (laminar flow) R ...