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Examples of rope and pulley systems illustrating mechanical advantage. Consider lifting a weight with rope and pulleys. A rope looped through a pulley attached to a fixed spot, e.g. a barn roof rafter, and attached to the weight is called a single pulley. It has a mechanical advantage (MA) = 1 (assuming frictionless bearings in the pulley ...
A fixed pulley changes the direction of the force on a rope or belt that moves along its circumference. Mechanical advantage is gained by combining a fixed pulley with a movable pulley or another fixed pulley of a different diameter. Movable: A movable pulley has an axle in a movable block. A single movable pulley is supported by two parts of ...
(see a hand-crank as an example.) In modern times, this kind of rotary leverage is widely used; see a (rotary) 2nd-class lever; see gears, pulleys or friction drive, used in a mechanical power transmission scheme. It is common for mechanical advantage to be manipulated in a 'collapsed' form, via the use of more than one gear (a gearset).
A block and tackle [1] [2] or only tackle [3] is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift heavy loads.. The pulleys are assembled to form blocks and then blocks are paired so that one is fixed and one moves with the load.
These cellular movements can be directed by external stimuli, a phenomenon known as taxis. Examples include chemotaxis (movement along chemical gradients) and phototaxis (movement in response to light). Motility also includes physiological processes like gastrointestinal movements and peristalsis.
Belts are looped over pulleys and may have a twist between the pulleys, and the shafts need not be parallel. In a two pulley system, the belt can either drive the pulleys normally in one direction (the same if on parallel shafts), or the belt may be crossed, so that the direction of the driven shaft is reversed (the opposite direction to the ...
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 .
For example, the locomotion of the collembola, Orchesella cincta, in relation to water. With increased water saturation in the soil there is an increase in the direction of its movement towards the aimed place. [1] Klinokinesis: in which the frequency or rate of turning is proportional to stimulus intensity.