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Atwood Machine
The Atwood machine (or Atwood's machine) was invented in 1784 by the English mathematician George Atwood as a laboratory experiment to verify the mechanical laws of motion with constant acceleration. Atwood's machine is a common classroom demonstration used to illustrate principles of classical mechanics. The ideal Atwood machine consists of two objects of mass and , connected by an inextensible massless string over an ideal massless pulley. Both masses experience uniform acceleration. When , the machine is in neutral equilibrium regardless of the position of the weights. Equation for constant acceleration An equation for the acceleration can be derived by analyzing forces. Assuming a massless, inextensible string and an ideal massless pulley, the only forces to consider are: tension force (), and the weight of the two masses ( and ). To find an acceleration, consider the forces affecting each individual mass. Using Newton's second law (with a sign convention of derive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atwoods Machine
Atwoods Ranch & Home is a farm and ranch supply store chain based in Enid, Oklahoma, United States. Atwoods has 75 stores in five states: Arkansas, Kansas, Missouri, Oklahoma and Texas. Most of its stores are located in Oklahoma, Texas, and Arkansas. In addition to farm and ranch supplies, Atwoods stores sell clothing, lawn and garden items, tools, hardware, automotive supplies, sporting goods, pet supplies, firearms, and seasonal items. History The Atwoods Ranch and Home Goods story started over 60 years ago with founders Fern and Wilbur Atwood. They had a simple American dream and were willing to see it through. It began with a trip from Minnesota nearly 1,000 miles south to start a new business based on sincere practices with a neighborly smile. They landed in Enid, Okla., and opened their first store in 1960. Current Day Atwoods is run by Wilber and Ferns grandson Brian Atwood, and Brians son Preston Atwood. Enid, Oklahoma is home to the Corporate offices and northern dist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tension (physics)
In physics, tension is described as the pulling force transmitted axially by the means of a string, a rope, chain, or similar object, or by each end of a rod, truss member, or similar three-dimensional object; tension might also be described as the action-reaction pair of forces acting at each end of said elements. Tension could be the opposite of compression (physics), compression. At the atomic level, when atoms or molecules are pulled apart from each other and gain potential energy with a restoring force still existing, the restoring force might create what is also called tension. Each end of a string or rod under such tension could pull on the object it is attached to, in order to restore the string/rod to its relaxed length. Tension (as a transmitted force, as an action-reaction pair of forces, or as a restoring force) is measured in newton (unit), newtons in the International System of Units (or pounds-force in Imperial units). The ends of a string or other object transmitt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Wolfram Demonstrations Project
The Wolfram Demonstrations Project is an organized, open-source collection of small (or medium-size) interactive programs called Demonstrations, which are meant to visually and interactively represent ideas from a range of fields. It is hosted by Wolfram Research, whose stated goal is to bring computational exploration to a large population. At its launch, it contained 1300 demonstrations but has grown to over 10,000. The site won a Parents' Choice Award in 2008. Technology The Demonstrations run in '' Mathematica'' 6 or above and in '' Wolfram CDF Player'' which is a free modified version of Wolfram's ''Mathematica'' and available for Windows, Linux and macOS and can operate as a web browser plugin. They typically consist of a very direct user interface to a graphic or visualization, which dynamically recomputes in response to user actions such as moving a slider, clicking a button, or dragging a piece of graphics. Each Demonstration also has a brief description of the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swinging Atwood's Machine
The swinging Atwood's machine (SAM) is a mechanism that resembles a simple Atwood's machine except that one of the masses is allowed to swing in a two-dimensional plane, producing a dynamical system that is chaotic for some system parameters and initial conditions. Specifically, it comprises two masses (the pendulum, mass and counterweight, mass ) connected by an inextensible, massless string suspended on two frictionless pulleys of zero radius such that the pendulum can swing freely around its pulley without colliding with the counterweight. The conventional Atwood's machine allows only "runaway" solutions (''i.e.'' either the pendulum or counterweight eventually collides with its pulley), except for M=m. However, the swinging Atwood's machine with M>m has a large parameter space of conditions that lead to a variety of motions that can be classified as terminating or non-terminating, periodic, quasiperiodic or chaotic, bounded or unbounded, singular or non-singular due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spherical Cow
Comic of a spherical cow as illustrated by a 1996 meeting of the American Astronomical Association, in reference to astronomy modeling The spherical cow is a humorous metaphor for highly simplified scientific models of complex phenomena. Originating in theoretical physics, the metaphor refers to physicists' tendency to reduce a problem to the simplest form imaginable in order to make calculations more feasible, even if the simplification hinders the model's application to reality. The metaphor and variants have subsequently been used in other disciplines. History The phrase comes from a joke that spoofs the simplifying assumptions sometimes used in theoretical physics. It is told in many variants, including a joke about a physicist who said he could predict the winner of any race provided it involved spherical horses moving through a vacuum. A 1973 letter to the editor in the journal ''Science'' describes the "famous story" about a physicist whose solution to a poultry far ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kater's Pendulum
A Kater's pendulum is a reversible free swinging pendulum invented by British physicist and army captain Henry Kater in 1817 for use as a gravimeter instrument to measure the local acceleration of gravity. Its advantage is that, unlike previous pendulum gravimeters, the pendulum's centre of gravity and center of oscillation do not have to be determined, allowing a greater accuracy. For about a century, until the 1930s, Kater's pendulum and its various refinements remained the standard method for measuring the strength of the Earth's gravity during geodetic surveys. It is now used only for demonstrating pendulum principles. Description A pendulum can be used to measure the acceleration of gravity ''g'' because for narrow swings its period of swing ''T'' depends only on ''g'' and its length ''L'': :T = 2 \pi \sqrt \qquad \qquad \qquad (1)\, So by measuring the length ''L'' and period ''T'' of a pendulum, ''g'' can be calculated. The Kater's pendulum consists of a rigid metal b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frictionless Plane
The frictionless plane is a concept from the writings of Galileo Galilei. In his 1638 '' The Two New Sciences'', Galileo presented a formula that predicted the motion of an object moving down an inclined plane. His formula was based upon his past experimentation with free-falling bodies. However, his model was not based upon experimentation with objects moving down an inclined plane, but from his conceptual modeling of the forces acting upon the object. Galileo understood the mechanics of the inclined plane as the combination of horizontal and vertical vectors; the result of gravity acting upon the object, diverted by the slope of the plane. However, Galileo's equations do not contemplate friction, and therefore do not perfectly predict the results of an actual experiment. This is because some energy is always lost when one mass applies a non-zero normal force to another. Therefore, the observed speed, acceleration and distance traveled should be less than Galileo predicts. This en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boat Lift
A boat lift, ship lift, or lift lock is a machine for transporting boats between water at two different elevations, and is an alternative to the canal lock. It may be vertically moving, like the Anderton boat lift in England, rotational, like the Falkirk Wheel in Scotland, or operate on an inclined plane, like the Ronquières inclined plane in Belgium. History A precursor to the canal boat lift, able to move full-sized canal boats, was the tub boat lift used in mining, able to raise and lower the 2.5 ton tub boats then in use. An experimental system was in use on the Churprinz mining canal in Halsbrücke near Dresden. It lifted boats using a moveable hoist rather than caissons. The lift operated between 1789 and 1868,Charles Hadfield ''World Canals: Inland Navigation Past and Present'', p. 71, and for a period of time after its opening engineer James Green reporting that five had been built between 1796 and 1830. He credited the invention to Dr James Anderson of Edinburgh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Funicular
A funicular (, , ) is a type of cable railway system that connects points along a railway track laid on a steep slope. The system is characterized by two counterbalanced carriages (also called cars or trains) permanently attached to opposite ends of a haulage cable, which is looped over a pulley at the upper end of the track. The result of such a configuration is that the two carriages move synchronously: as one ascends, the other descends at an equal speed. This feature distinguishes funiculars from inclined elevators, which have a single car that is hauled uphill. The term ''funicular'' derives from the Latin word , the diminutive of , meaning 'rope'. Operation In a funicular, both cars are permanently connected to the opposite ends of the same cable, known as a ''haul rope''; this haul rope runs through a system of pulleys at the upper end of the line. If the railway track is not perfectly straight, the cable is guided along the track using sheaves – unpowered pulleys tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolling-element Bearing
In mechanical engineering, a rolling-element bearing, also known as a rolling bearing, is a bearing which carries a load by placing rolling elements (such as balls or rollers) between two concentric, grooved rings called races. The relative motion of the races causes the rolling elements to roll with very little rolling resistance and with little sliding. One of the earliest and best-known rolling-element bearings are sets of logs laid on the ground with a large stone block on top. As the stone is pulled, the logs roll along the ground with little sliding friction. As each log comes out the back, it is moved to the front where the block then rolls on to it. It is possible to imitate such a bearing by placing several pens or pencils on a table and placing an item on top of them. See " bearings" for more on the historical development of bearings. A rolling element rotary bearing uses a shaft in a much larger hole, and cylinders called "rollers" tightly fill the space between t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torque
In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of the body. The concept originated with the studies by Archimedes of the usage of levers, which is reflected in his famous quote: "''Give me a lever and a place to stand and I will move the Earth''". Just as a linear force is a push or a pull, a torque can be thought of as a twist to an object around a specific axis. Torque is defined as the product of the magnitude of the perpendicular component of the force and the distance of the line of action of a force from the point around which it is being determined. The law of conservation of energy can also be used to understand torque. The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. When being referred to as moment of force, it is commonly denoted by . In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moment Of Inertia
The moment of inertia, otherwise known as the mass moment of inertia, angular mass, second moment of mass, or most accurately, rotational inertia, of a rigid body is a quantity that determines the torque needed for a desired angular acceleration about a rotational axis, akin to how mass determines the force needed for a desired acceleration. It depends on the body's mass distribution and the axis chosen, with larger moments requiring more torque to change the body's rate of rotation. It is an extensive (additive) property: for a point mass the moment of inertia is simply the mass times the square of the perpendicular distance to the axis of rotation. The moment of inertia of a rigid composite system is the sum of the moments of inertia of its component subsystems (all taken about the same axis). Its simplest definition is the second moment of mass with respect to distance from an axis. For bodies constrained to rotate in a plane, only their moment of inertia about an axis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
