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- Ecosystem, the complex of living organisms, their physical environment, and all their interrelationships in a particular unit of space. An ecosystem can be categorized into its abiotic constituents, including minerals, climate, soil, water, and sunlight, and its biotic constituents, consisting of all living members.
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What is an ecosystem?
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What is a simple machine?
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May 23, 2024 · Ecosystem, the complex of living organisms, their physical environment, and all their interrelationships in a particular unit of space. An ecosystem can be categorized into its abiotic constituents, including minerals, climate, soil, water, and sunlight, and its biotic constituents, consisting of all living members.
- The Editors of Encyclopaedia Britannica
- Lever. A lever consists of a beam resting on a support. When a force is applied at a point on the beam, it rotates about the support point. The function of a lever is to multiply the applied force so that a heavy object can be raised.
- Inclined Plane. An inclined plane is the simplest of all simple machines. It does not consist of any moving parts, neither does it move. An inclined plane consists of a slope that makes a fixed angle to the surface on which it rests.
- Wedge. A wedge has a triangular shape and comprises one or two incline planes. A wedge made up of two incline planes has a sharp edge when the planes meet.
- Wheel and Axle. A wheel and axle consists of a large disc (wheel) and a long rod or shaft (axle). A rotational force or torque is applied to one part, which then rotates and transmits the force to the other part.
- Overview
- The inclined plane
- The lever
- The wedge
- The wheel and axle
simple machine, any of several devices with few or no moving parts that are used to modify motion and the magnitude of a force in order to perform work. They are the simplest mechanisms known that can use leverage (or mechanical advantage) to increase force. The simple machines are the inclined plane, lever, wedge, wheel and axle, pulley, and screw...
An inclined plane consists of a sloping surface; it is used for raising heavy bodies. The plane offers a mechanical advantage in that the force required to move an object up the incline is less than the weight being raised (discounting friction). The steeper the slope, or incline, the more nearly the required force approaches the actual weight. Expressed mathematically, the force F required to move a block D up an inclined plane without friction is equal to its weight W times the sine of the angle the inclined plane makes with the horizontal (θ). The equation is F = W sin θ.
The principle of the inclined plane is used widely—for example, in ramps and switchback roads, where a small force acting for a distance along a slope can do a large amount of work.
A lever is a bar or board that rests on a support called a fulcrum. A downward force exerted on one end of the lever can be transferred and increased in an upward direction at the other end, allowing a small force to lift a heavy weight.
Britannica Quiz
Machinery and Manufacturing
All early people used the lever in some form, for example, for moving heavy stones or as digging sticks for land cultivation. The principle of the lever was used in the swape, or shadoof, a long lever pivoted near one end with a platform or water container hanging from the short arm and counterweights attached to the long arm. A man could lift several times his own weight by pulling down on the long arm. This device is said to have been used in Egypt and India for raising water and lifting soldiers over battlements as early as 1500 bce.
A wedge is an object that tapers to a thin edge. Pushing the wedge in one direction creates a force in a sideways direction. It is usually made of metal or wood and is used for splitting, lifting, or tightening, as in securing a hammer head onto its handle.
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The wedge was used in prehistoric times to split logs and rocks; an ax is also a wedge, as are the teeth on a saw. In terms of its mechanical function, the screw may be thought of as a wedge wrapped around a cylinder.
A wheel and axle is made up of a circular frame (the wheel) that revolves on a shaft or rod (the axle). In its earliest form it was probably used for raising weights or water buckets from wells.
Its principle of operation is best explained by way of a device with a large gear and a small gear attached to the same shaft. The tendency of a force, F, applied at the radius R on the large gear to turn the shaft is sufficient to overcome the larger force W at the radius r on the small gear. The force amplification, or mechanical advantage, is equal to the ratio of the two forces (W:F) and also equal to the ratio of the radii of the two gears (R:r).
If the large and small gears are replaced with large- and small-diameter drums that are wrapped with ropes, the wheel and axle becomes capable of raising weights. The weight being lifted is attached to the rope on the small drum, and the operator pulls the rope on the large drum. In this arrangement the mechanical advantage is the radius of the large drum divided by the radius of the small drum. An increase in the mechanical advantage can be obtained by using a small drum with two radii, r1 and r2, and a pulley block. When a force is applied to the large drum, the rope on the small drum winds onto D and off of d.
A measure of the force amplification available with the pulley-and-rope system is the velocity ratio, or the ratio of the velocity at which the force is applied to the rope (VF) to the velocity at which the weight is raised (VW). This ratio is equal to twice the radius of the large drum divided by the difference in the radii of the smaller drums D and d. Expressed mathematically, the equation is VF/VW = 2R/(r2 - r1). The actual mechanical advantage W/F is less than this velocity ratio, depending on friction. A very large mechanical advantage may be obtained with this arrangement by making the two smaller drums D and d of nearly equal radius.
- The Editors of Encyclopaedia Britannica
Ecosystems and biomes. Ecosystems, made up of living and non-living things, can be as small as a tide pool or as big as a rainforest. Ecosystems can be classified as terrestrial or aquatic, with aquatic further divided into marine and freshwater.
- 8 min
- Sal Khan
Dec 1, 2005 · Frank Golley refers to the ecosystem concept as “a machine theory applied to nature,” but ecosystems continue to hover among and between all three of our figures, simultaneously bearing features of organisms, machines, and thunderstorms ( Golley 1993 ).
Mar 28, 2024 · Ecosystem Definition. An ecosystem is a system consisting of biotic and abiotic components that function together as a unit. The biotic components include all the living things whereas the abiotic components are the non-living things. Thus, an ecosystem science definition entails an ecological community consisting of different populations of ...
An ecosystem is a community of living organisms and their interactions with their abiotic (non-living) environment. Ecosystems can be small, such as the tide pools found near the rocky shores of many …
