mindmap root((DYNAM)) dynamic 1、 Relating to physical force or energy.
2、 Continuously and productively active and changing; energetic or forceful.
🌱The situation has entered a dynamic phase, and what we knew about it last week has changed considerably by now. 🌳Dynamic is the opposite of static, which means "not moving or active." So all living languages, for example, are dynamic rather than static, changing from year to year even when they don't appear to be. A bustling commercial city like Hong Kong is intensely dynamic, constantly changing and adapting. A dynamic relationship—for example, the relationship between housing values and interest rates charged by banks—is one that changes all the time. Unfortunately, the word has been used so much by advertisers that we tend to forget its basic meaning. dynamo 1、 A power generator, especially one that produces direct electric current.
2、 A forceful, energetic person.
🌱Even as they entered the power plant, the roar of the water covered the sound of the immense dynamos. 🌳The dynamo was introduced in 1832 to produce electricity for commercial use. Like all later generators, the original dynamos changed mechanical energy （produced by steam, which was itself produced by burning coal） into electricity. The word is less used today than it once was, since it's often applied only to generators that produced direct electric current （DC） rather than alternating current （AC）, which is now the standard. A human dynamo is a person who seems to have unlimited energy, such as New York's legendary mayor Fiorello La Guardia, whose forcefulness and vigor matched that of his intensely dynamic city. aerodynamics 1、 A science that studies the movement of gases such as air and the way that objects move through such gases.
2、 The qualities of an object that affect how easily it is able to move through the air.
🌱Early automobile designs were based on the boxlike carriages drawn by horses, back when no one was even thinking about aerodynamics. 🌳Aerodynamics began as a science around the time of the Wright brothers' first manned flights. Since then, it's become important to the building not only of aircraft and automobiles but also of rockets and missiles, trains, ships, and even such structures as bridges and tall buildings, which often have to withstand strong winds. An aerodynamic vehicle is one whose design helps it achieve the greatest speed and most efficient use of fuel. But although we might casually call any sleek car design aerodynamic, true aerodynamics is practiced not by artistic product designers but instead by highly trained scientists, and many people's lives depend on their work. hydrodynamic Having to do with the science that studies fluids in motion and the forces that act on bodies surrounded by fluids.
🌱Building levees to contain a flood presents complicated hydrodynamic problems. 🌳Bernoulli's principle, which is basic to the science of hydrodynamics, says that the faster a fluid substance flows, the less outward pressure it exerts. It shows the close relationship between hydrodynamics and aerodynamics （which deals with the movement of air and other gases）, since it can partly explain how air will "lift" an airplane by the way it flows over the wings, and how a spoiler helps keep a race car's wheels pressed to the ground as it accelerates. Hydrodynamics is sometimes applied today in studying the surface of the planets and even the stars. As used informally by boaters, hydrodynamic often means "hydrodynamically efficient."