Answer:
In vector calculus, the curl is a vector operator that describes the infinitesimal rotation of a vector field in three-dimensional Euclidean space. At every point in the field, the curl of that point is represented by a vector. The attributes of this vector (length and direction) characterize the rotation at that point. The direction of the curl is the axis of rotation, as determined by the right-hand rule, and the magnitude of the curl is the magnitude of rotation. If the vector field represents the flow velocity of a moving fluid, then the curl is the circulation density of the fluid. A vector field whose curl is zero is called irrotational. The curl is a form of differentiation for vector fields. The corresponding form of the fundamental theorem of calculus is Stokes' theorem, which relates the surface integral of the curl of a vector field to the line integral of the vector field around the boundary curve.
The alternative terminology rotation or rotational and alternative notations rot F and ∇ × F are often used (the former especially in many European countries, the latter, using the del (or nabla) operator and the cross product, is more used in other countries) for curl F.
Unlike the gradient and divergence, curl does not generalize as simply to other dimensions; some generalizations are possible, but only in three dimensions is the geometrically defined curl of a vector field again a vector field. This is a phenomenon similar to the 3-dimensional cross product, and the connection is reflected in the notation ∇ × for the curl.
Explanation:
When Wilhelm became kaiser, he was determined to present himself as a bold German warrior who would expand his nation's power. Germany, he declared, must have its "place in the sun" among the world's greatest nations. So he built up the German army and navy.
Canals and inland waterways, natural or artificial waterways used for ... The lay of the land (topography) and particularly changes in water levels ... inland waterway transport is still more economical than any other kind of transport.
Answer: B. Buoyancy
Explanation: The asthenosphere exerts a buoyant force that pushes up against the lithosphere, and this force resists gravity. The theory of isostasy refers to an equilibrium in buoyancy between the lithosphere and the asthenosphere.
