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:
between Europe and Asia (dividing Eurasia): along the Turkish Straits, the Caucasus and the Urals (historically also north of the Caucasus, along the Kuma–Manych Depression or along the Don River) between Asia and Africa (dividing Afro-Eurasia into Africa and Eurasia): at the Isthmus of Suez.
Answer:
Use sunrise and sunset for approximate directions.
Face the sunrise and you are facing east; north will be on your left and south will be on your right. Face the sunset and you are facing west; north will be on your right and south will be on your left.
Answer:
Transitional Stage
Explanation:
Declining death rates due to increased food production and improved medical care while birth rates remain high is characteristic of the TRANSITIONAL stage of the demographic transition.
The human population continues to increase at this point because of rising birth rates and declining death rates. The death rates are declining as there are changes in the economy and social conditions as the country transforms into an developed society.
The theory of demographic change is a theoretical explanation of rising mortality, fertility, and rates of growth as populations shift from one demographic system to another.
Answer:
1. Salts. 2. Oil reserves. 3. Gold deposits. 4. Minerals
Explanation:
- As oceans are the lifeblood of the planet they give all the natural resources that we need to live a healthy and economic life. Seafloor contains various features like volcanic vents and trenches. These vents contain massive seafloor sulfur contents.
- Also, they consist of high-value items like gold, silver deposits as these have been constantly been drilled for such precious metals. Similarly, various minerals and salt content ate known to have been found in these deposits.
- The presence of active deposits is found near the continental plate boundary. Certain SEZ special economic zones have neb thus made to help preserve the mineral and oil wealth of nations.
