A simple machine is a non-motorized device that changes the direction or magnitude of a force. In general, a simple machine can be defined as one of the simplest mechanisms that provide mechanical advantage (also called leverage).
Usually the term refers to the six classical simple machines which were defined by Renaissance scientists:
Mechanical engineering is a discipline of engineering that applies the principles of engineering, physics and materials science for analysis, design, manufacturing, and maintenance of mechanical systems. It is the branch of engineering that involves the production and usage of heat and mechanical power for the design, production, and operation of machines and tools. It is one of the oldest and broadest engineering disciplines.
The engineering field requires an understanding of core concepts including mechanics, kinematics, thermodynamics, materials science, structural analysis, and electricity. Mechanical engineers use these core principles along with tools like computer-aided engineering, and product lifecycle management to design and analyze manufacturing plants, industrial equipment and machinery, heating and cooling systems, transport systems, aircraft, watercraft, robotics, medical devices, weapons, and others.
Seesaw or disphenoidal is a type of molecular geometry where there are four bonds to a central atom with overall C2v symmetry. The name "seesaw" comes from the observation that it looks like a seesaw. Most commonly, four bonds to a central atom result in tetrahedral or, less commonly, square planar geometry, so the seesaw geometry, just like its name, is unusual.
It occurs when a molecule has a steric number of 5, with the central atom being bonded to 4 other atoms and 1 lone pair. An atom bonded to 5 other atoms (and no lone pairs) forms a trigonal bipyramid; but in this case one of the atoms is replaced by a lone pair. The atom replaced is always an equatorial atom, because the lone pairs repel other electrons more strongly than atoms do.
The compound lever is a simple machine operating on the premise that the resistance from one lever in a system of levers will act as power for the next, and thus the applied force will be amplified from one lever to the next (as long as the mechanical advantage for each lever is greater than one). Almost all scales use some sort of compound lever to work. Other examples include nail clippers and piano keys.
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