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Fluid friction describes the friction between layers of a viscous fluid that are moving relative to each other. [7] [8] Lubricated friction is a case of fluid friction where a lubricant fluid separates two solid surfaces. [9] [10] [11] Skin friction is a component of drag, the force resisting the motion of a fluid across the surface of a body.
The history of fluid mechanics is a fundamental strand of the history of physics and engineering.The study of the movement of fluids (liquids and gases) and the forces that act upon them dates back to pre-history.
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
The first English use of the expression "meaning of life" appears in Thomas Carlyle's Sartor Resartus (1833–1834), book II chapter IX, "The Everlasting Yea". [1]Our Life is compassed round with Necessity; yet is the meaning of Life itself no other than Freedom, than Voluntary Force: thus have we a warfare; in the beginning, especially, a hard-fought battle.
Tribology is the science and engineering of understanding friction, lubrication and wear phenomena for interacting surfaces in relative motion.It is highly interdisciplinary, drawing on many academic fields, including physics, chemistry, materials science, mathematics, biology and engineering. [1]
Research concerning the relationship between the thermodynamic quantity entropy and both the origin and evolution of life began around the turn of the 20th century. In 1910 American historian Henry Adams printed and distributed to university libraries and history professors the small volume A Letter to American Teachers of History proposing a theory of history based on the second law of ...
Rumford was heavily influenced by the argument from design [4] and it is likely that he wished to grant water a privileged and providential status in the regulation of human life. [ 5 ] Though Rumford was to come to associate heat with motion , there is no evidence that he was committed to the kinetic theory or the principle of vis viva .
Early micro-fossils may have come from a hot world of gases such as methane, ammonia, carbon dioxide, and hydrogen sulfide, toxic to much current life. [229] Analysis of the tree of life places thermophilic and hyperthermophilic bacteria and archaea closest to the root, suggesting that life may have evolved in a hot environment. [ 230 ]