lever

leverdiagram of the three types of levers, showing fulcrum, direction of effort, and direction of force of the load (or resistance)top: a crowbarcenter: a wheelbarrowbottom: a shovel

lev·er

L0138200 (lĕv′ər, lē′vər)n.1. A simple machine consisting of a rigid bar pivoted on a fixed point and used to transmit force, as in raising or moving a weight at one end by pushing down on the other.2. A projecting handle used to adjust or operate a mechanism.3. A means of accomplishing; a tool: used friendship as a lever to obtain advancement.tr.v. lev·ered, lev·er·ing, lev·ers 1. To move or lift with a lever: levered up the manhole cover.2. To move (oneself, for example) in a manner resembling the use of a lever: "[He] levered himself out the window all the way to his waist" (Stephen King).3. To fund at least in part with borrowed money; leverage.

[Middle English, from Old French levier, from lever, to raise, from Latin levāre, from levis, light; see leg^wh- in Indo-European roots.]

lever

(ˈliːvə) n1. (Mechanical Engineering) a rigid bar pivoted about a fulcrum, used to transfer a force to a load and usually to provide a mechanical advantage2. (Mechanical Engineering) any of a number of mechanical devices employing this principle3. a means of exerting pressure in order to accomplish something; strategic aidvb (Mechanical Engineering) to prise or move (an object) with a lever[C13: from Old French leveour, from lever to raise, from Latin levāre, from levis light] ˈlever-ˌlike adj

lev•er

(ˈlɛv ər, ˈli vər)
n. 1. a rigid bar that pivots about one point and that is used to move an object at a second point by a force applied at a third. 2. a means or agency of persuading or of achieving an end. v.t. 3. to move or lift with or as if with a lever. v.i. 4. to use a lever. [1250–1300; Middle English levere, levour for *lever < Anglo-French; Old French levier=lev(er) to lift (< Latin levāre to lighten, lift) + -ier -ier²]

lev·er

(lĕv′ər) A simple machine consisting of a bar that pivots on a fixed support, the fulcrum, and is used to transmit force. For example, a lever with the fulcrum positioned between the two ends can raise or move a heavy weight at one end as the bar is pushed down at the other. See more at fulcrum.

lever

Past participle: levered
Gerund: levering

Imperative
lever
lever

Present
I lever
you lever
he/she/it levers
we lever
you lever
they lever

Preterite
I levered
you levered
he/she/it levered
we levered
you levered
they levered

Present Continuous
I am levering
you are levering
he/she/it is levering
we are levering
you are levering
they are levering

Present Perfect
I have levered
you have levered
he/she/it has levered
we have levered
you have levered
they have levered

Past Continuous
I was levering
you were levering
he/she/it was levering
we were levering
you were levering
they were levering

Past Perfect
I had levered
you had levered
he/she/it had levered
we had levered
you had levered
they had levered

Future
I will lever
you will lever
he/she/it will lever
we will lever
you will lever
they will lever

Future Perfect
I will have levered
you will have levered
he/she/it will have levered
we will have levered
you will have levered
they will have levered

Future Continuous
I will be levering
you will be levering
he/she/it will be levering
we will be levering
you will be levering
they will be levering

Present Perfect Continuous
I have been levering
you have been levering
he/she/it has been levering
we have been levering
you have been levering
they have been levering

Future Perfect Continuous
I will have been levering
you will have been levering
he/she/it will have been levering
we will have been levering
you will have been levering
they will have been levering

Past Perfect Continuous
I had been levering
you had been levering
he/she/it had been levering
we had been levering
you had been levering
they had been levering

Conditional
I would lever
you would lever
he/she/it would lever
we would lever
you would lever
they would lever

Past Conditional
I would have levered
you would have levered
he/she/it would have levered
we would have levered
you would have levered
they would have levered

lever

A rigid bar turned about a fixed point (fulcrum) to support or move a load; a simple form of machine.

Thesaurus

Noun	1.	lever - a rigid bar pivoted about a fulcrumbar - a rigid piece of metal or wood; usually used as a fastening or obstruction or weapon; "there were bars in the windows to prevent escape"compound lever - a pair of levers hinged at the fulcrumcrowbar, pry, pry bar, wrecking bar - a heavy iron lever with one end forged into a wedgefulcrum - the pivot about which a lever turnsgun trigger, trigger - lever that activates the firing mechanism of a gunhand throttle - a hand-operated lever that controls the throttle valvekey - a lever (as in a keyboard) that actuates a mechanism when depressedcant dog, dog hook, peavey, peavy - a stout lever with a sharp spike; used for handling logsfoot lever, foot pedal, treadle, pedal - a lever that is operated with the footpinch bar - a lever with a pointed projection that serves as a fulcrum; used to roll heavy wheelsripping bar - a steel lever with one end formed into a ripping chisel and the other a gooseneck with a claw for pulling nailsrocker arm, valve rocker - a lever pivoted at the center; used especially to push a valve down in an internal-combustion enginespark lever - (on early automobiles) a lever mounted on the steering column and used to adjust the timing of the ignitioncontrol stick, joystick, stick - a lever used by a pilot to control the ailerons and elevators of an airplanetappet - a lever that is moved in order to tap something elsetiller - lever used to turn the rudder on a boattire iron, tire tool - hand tool consisting of a lever that is used to force the casing of a pneumatic tire onto a steel wheel
	2.	lever - a simple machine that gives a mechanical advantage when given a fulcrumsimple machine, machine - a device for overcoming resistance at one point by applying force at some other point
	3.	lever - a flat metal tumbler in a lever locklever tumblerlever lock - a lock whose tumblers are levers that must be raised to a given position so that the bolt can movetumbler - a movable obstruction in a lock that must be adjusted to a given position (as by a key) before the bolt can be thrown
Verb	1.	lever - to move or force, especially in an effort to get something open; "The burglar jimmied the lock": "Raccoons managed to pry the lid off the garbage pail"jimmy, prise, pry, prizeopen, open up - cause to open or to become open; "Mary opened the car door"

lever

noun1. handle, bar, crowbar, jemmy, handspike Robert leaned lightly on the lever and the rock groaned.verb1. prise, move, force, raise, pry (U.S.), jemmy Neighbours eventually levered the door open with a crowbar.

Translations

杠杆用杠杆撬动控制杆

lever

(ˈliːvə) , ((American) ˈlevər) noun1. a bar of wood, metal etc used to lift heavy weights. A crowbar is a kind of lever; You must use a coin as a lever to get the lid of that tin off.杠杆2. a bar or handle for operating a machine etc. This is the lever that switches on the power.控制杆 verb to move with or as if with a lever. He levered the lid off with a coin.用杠杆撬动ˈleverage (-ridʒ) noun1. the power gained by the use of a lever. 杠杆作用2. power that can be used to influence someone's actions or decisions. The public has some leverage with their representatives in the Senate. 影响力，力量

lever

→ 杠杆zhCN

lever

lever,

simple machinemachine,
arrangement of moving and stationary mechanical parts used to perform some useful work or to provide transportation. From a historical perspective, many of the first machines were the result of human efforts to improve war-making capabilities; the term engineer
..... Click the link for more information. consisting of a bar supported at some stationary point along its length and used to overcome resistance at a second point by application of force at a third point. The stationary point of a lever is known as its fulcrum. The term lever is also applied to a projecting piece that is moved to operate or adjust inner machinery, such as a lever moved to the right or left to switch electric current on or off or to adjust the size of the opening of a shutter in a camera.

Principle of the Lever

It has been found by experiment that two equal forces acting in opposite directions, i.e., clockwise and counterclockwise, and applied to a uniform lever at equal distances from the fulcrum counteract each other and establish a state of equilibriumequilibrium,
state of balance. When a body or a system is in equilibrium, there is no net tendency to change. In mechanics, equilibrium has to do with the forces acting on a body.
..... Click the link for more information. , or balance, in the lever. Experiment has also shown that two unequal forces when acting in opposite directions will bring about an equilibrium when the product of the magnitude of one force and its effort arm, or lever arm (the distance of its point of application from the fulcrum), is equal to the product of the magnitude of the other force and its effort arm. In physics the product of a force by its effort arm is called a momentmoment,
in physics and engineering, term designating the product of a quantity and a distance (or some power of the distance) to some point associated with that quantity.
..... Click the link for more information. of the force; the general conclusion known as the principle of moments states that equilibrium is established when the sum of the moments of the forces acting in a clockwise direction is equal to the sum of the moments of the forces acting in a counterclockwise direction. It is possible, as a result, to overcome a very large force at a short distance from the fulcrum with a very small force at a great distance from the fulcrum. Archimedes is supposed to have boasted, having the lever in mind, that given a place to stand he could move the world.

Classification and Application of Levers

In the use of a small force to overcome a large one the lever finds its many common applications. The lever is used for prying, as in the case of the crowbar, or for lifting. For example, the fulcrum is the point upon which a crowbar rests when used to lift or to pry loose some object; the effort is applied at the end farther from the fulcrum and is relatively small. The distance from the operator's hands to the fulcrum is known as the lever arm, or effort arm; the object being pried loose is the resisting force, or resistance; the object's distance from the fulcrum is the resistance arm. Levers in which the fulcrum is located between the effort and the resistance, as in the crowbar and the beam balance, are known as first-class levers. The fulcrum may also be located at one end of the lever, with the effort applied at the other end and the resistance in between; this type of lever, illustrated by the wheelbarrow and the nutcracker, is known as a second-class lever. The final possibility, known as a third-class lever, has the effort applied between the fulcrum and the resistance and is illustrated by various types of tongs.

Many other common tools, instruments, and appliances are applications of the principle of the lever. The human forearm is an application of the third-class lever, the elbow acting as the fulcrum, the weight held in the hand and being lifted as the resistance, and the pull of the muscles between the elbow and the hand as the effort. In a second-class lever, the effort arm is always longer than the resistance arm, so that a smaller effort moves a larger resistance, while in a third-class lever the reverse is always true, with the effort greater than the resistance. In a first-class lever, the effort may be either larger or smaller than the resistance, depending upon the location of the fulcrum.

Lever

a simple machine consisting of a rigid element that pivots about a fixed support (fulcrum) and enables a smaller force to balance a larger one. The operating principle behind any type of lever can be expressed by the equality Ph₁ = Qh₂, where P and Q are the applied forces, and h₁ and h₂ are the lever arms, that is the perpendicular distances from the fulcrum to the line of action of each force.

Figure 1. Levers: (a) first-class, (b) second-class

If the fulcrum is positioned between the points where the forces are applied, the machine is called a first-class lever (Figure 1, a). If both forces are applied on the same side of the fulcrum, the machine is a second-class lever (Figure 1, b). With first-class levers, the forces must take the same general direction; with second-class levers, the forces assume different directions. Archimedes developed the theory of equilibrium for levers balanced by weights, and the general condition for lever equilibrium was worked out by P. Varignon in 1687. Levers are often used as simple lifting devices.

lever

[′lev·ər, lē·vər] (engineering) A rigid bar, pivoted about a fixed point (fulcrum), used to multiply force or motion; used for raising, prying, or dislodging an object.

lever

1. a rigid bar pivoted about a fulcrum, used to transfer a force to a load and usually to provide a mechanical advantage 2. any of a number of mechanical devices employing this principle

lever

lev·er

lever

lev•er

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lever

lever

lever,

Principle of the Lever

Classification and Application of Levers

Lever

lever

lever

lever

lev·er

lev·er

lever

Synonyms for lever

noun handle

Synonyms

verb prise

Synonyms

Synonyms for lever

noun a rigid bar pivoted about a fulcrum

Related Words

noun a simple machine that gives a mechanical advantage when given a fulcrum

Related Words

noun a flat metal tumbler in a lever lock

Synonyms

Related Words

verb to move or force, especially in an effort to get something open

Synonyms

Related Words