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33-1078: For the pruning tool, see loppers . [REDACTED] Look up loper in Wiktionary, the free dictionary. Loper is a surname. People with this surname include: Alonzo A. Loper (1829–1917), American politician Bert Loper (1869–1949), early Grand Canyon river runner Brad Loper (born 1970), American photojournalist Daniel Loper (born 1982), American football offensive tackle David Loper ( fl.  1990s–present ), American geologist Don Loper (1906–1972), American costume and necktie designer Edward L. Loper, Sr. (1916–2011), African American artist James Loper (1931–2013), American television executive Johnny Loper ( fl.  1950s–1960s ), American drag racer Herbert Loper (1896–1989), American general Whitly Loper (born 1986), American sport shooter Ron Loper Jr (born 2007), American rapper/music artist See also [ edit ] Loper Bright Enterprises v. Raimondo (2024),

66-638: A ( F A ⋅ e A ⊥ ) − b ( F B ⋅ e B ⊥ ) = a F A − b F B , {\displaystyle F_{\theta }=\mathbf {F} _{A}\cdot {\frac {\partial \mathbf {v} _{A}}{\partial {\dot {\theta }}}}-\mathbf {F} _{B}\cdot {\frac {\partial \mathbf {v} _{B}}{\partial {\dot {\theta }}}}=a(\mathbf {F} _{A}\cdot \mathbf {e} _{A}^{\perp })-b(\mathbf {F} _{B}\cdot \mathbf {e} _{B}^{\perp })=aF_{A}-bF_{B},} where F A and F B are components of

99-426: A b . {\displaystyle MA={\frac {F_{2}}{F_{1}}}={\frac {a}{b}}.\!} This relationship shows that the mechanical advantage can be computed from ratio of the distances from the fulcrum to where the input and output forces are applied to the lever, assuming a weightless lever and no losses due to friction, flexibility or wear. This remains true even though the "horizontal" distance (perpendicular to

132-403: A b . {\displaystyle MA={\frac {F_{B}}{F_{A}}}={\frac {a}{b}}.} This is the law of the lever , which was proven by Archimedes using geometric reasoning. It shows that if the distance a from the fulcrum to where the input force is applied (point A ) is greater than the distance b from fulcrum to where the output force is applied (point B ), then the lever amplifies

165-406: A and b are distances from the fulcrum to points A and B and the force F A applied to A is the input and the force F B applied at B is the output, the ratio of the velocities of points A and B is given by a/b , so we have the ratio of the output force to the input force, or mechanical advantage, is given by: M A = F B F A =

198-493: A US Supreme Court case [REDACTED] Surname list This page lists people with the surname Loper . If an internal link intending to refer to a specific person led you to this page, you may wish to change that link by adding the person's given name (s) to the link. Retrieved from " https://en.wikipedia.org/w/index.php?title=Loper&oldid=1251556562 " Category : Surnames Hidden categories: Articles with short description Short description

231-402: A bypass lopper so that material either binds between the blades or even levers them apart, which can be dangerous both to the tool and the operator. Both types of lopper generally have a sprung adjusting screw at the fulcrum , which can be used to tighten the blades as they loosen in use. With bypass loppers, it is also useful for releasing material jamming the blades. Anvil loppers usually have

264-401: A fixed point. The lever operates by applying forces at different distances from the fulcrum, or a pivot. As the lever rotates around the fulcrum, points further from this pivot move faster than points closer to the pivot. Therefore, a force applied to a point further from the pivot must be less than the force located at a point closer in, because power is the product of force and velocity. If

297-426: A screw for adjusting or detaching the plate, so that it can be moved to compensate for wear or replaced entirely. Fulcrum (mechanics) A lever is a simple machine consisting of a beam or rigid rod pivoted at a fixed hinge , or fulcrum . A lever is a rigid body capable of rotating on a point on itself. On the basis of the locations of fulcrum, load and effort, the lever is divided into three types . It

330-507: A single sharpened blade, with a straight or sometimes curved edge, that closes against a similarly contoured flat anvil like surface on the other side of the jaws, usually made of a softer metal than the blade. Anvil loppers have the disadvantage of tending to crush rather than cut, sometimes leaving an untidy wound, more vulnerable to infection. Their main advantages are of relative strength and of being less likely to jam with fibrous material. Very hard or resilient branches can sometimes deflect

363-419: Is between bypass and anvil types. Bypass loppers operate like scissors, except that they generally only have one blade that moves past a jaw or hook that has an approximately square edge that is not typically sharpened and is usually concave or hook shaped in order keep branches from slipping out of the jaws. The jaws of bypass loppers may be straight, curved, or one curved with one straight. Anvil loppers have

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396-417: Is different from Wikidata All set index articles Loppers They are usually operated with two hands, and with handles typically between 30 centimetres (12 in) and 91 centimetres (36 in) long to give good leverage. Some have telescopic handles which can be extended to a length of two metres, in order to increase leverage and to reach high branches on a tree. Loppers are mainly used for

429-451: Is evident from the recesses in the large blocks and the handling bosses which could not be used for any purpose other than for levers. The earliest remaining writings regarding levers date from the 3rd century BC and were provided, by common belief, by the Greek mathematician Archimedes , who famously stated "Give me a lever long enough and a fulcrum on which to place it, and I shall move

462-415: Is lessened. T 1 = F 1 a , T 2 = F 2 b {\displaystyle {\begin{aligned}T_{1}&=F_{1}a,\quad \\T_{2}&=F_{2}b\!\end{aligned}}} where F 1 is the input force to the lever and F 2 is the output force. The distances a and b are the perpendicular distances between

495-482: Is one of the six simple machines identified by Renaissance scientists. A lever amplifies an input force to provide a greater output force, which is said to provide leverage , which is mechanical advantage gained in the system, equal to the ratio of the output force to the input force. As such, the lever is a mechanical advantage device , trading off force against movement. The word "lever" entered English around AD 1300 from Old French : levier . This sprang from

528-405: Is operated by applying an input force F A at a point A located by the coordinate vector r A on the bar. The lever then exerts an output force F B at the point B located by r B . The rotation of the lever about the fulcrum P is defined by the rotation angle θ in radians. Let the coordinate vector of the point P that defines the fulcrum be r P , and introduce

561-481: Is the generalized coordinate that defines the configuration of the lever, and the generalized force associated with this coordinate is given by F θ = F A ⋅ ∂ v A ∂ θ ˙ − F B ⋅ ∂ v B ∂ θ ˙ =

594-447: The ancient Near East c.  5000 BC , when it was first used in a simple balance scale . In ancient Egypt c.  4400 BC , a foot pedal was used for the earliest horizontal frame loom . In Mesopotamia (modern Iraq) c.  3000 BC , the shadouf , a crane-like device that uses a lever mechanism, was invented. In ancient Egypt , workmen used the lever to move and uplift obelisks weighing more than 100 tons. This

627-442: The forces and the fulcrum. Since the moments of torque must be balanced, T 1 = T 2 {\displaystyle T_{1}=T_{2}\!} . So, F 1 a = F 2 b {\displaystyle F_{1}a=F_{2}b\!} . The mechanical advantage of a lever is the ratio of output force to input force. M A = F 2 F 1 =

660-400: The forces that are perpendicular to the radial segments PA and PB . The principle of virtual work states that at equilibrium the generalized force is zero, that is F θ = a F A − b F B = 0. {\displaystyle F_{\theta }=aF_{A}-bF_{B}=0.\,\!} Thus, the ratio of the output force F B to

693-426: The input force F A is obtained as M A = F B F A = a b , {\displaystyle MA={\frac {F_{B}}{F_{A}}}={\frac {a}{b}},} which is the mechanical advantage of the lever. This equation shows that if the distance a from the fulcrum to the point A where the input force is applied is greater than the distance b from fulcrum to

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726-419: The input force. On the other hand, if the distance a from the fulcrum to the input force is less than the distance b from the fulcrum to the output force, then the lever reduces the input force. The use of velocity in the static analysis of a lever is an application of the principle of virtual work . A lever is modeled as a rigid bar connected to a ground frame by a hinged joint called a fulcrum. The lever

759-442: The lengths a = | r A − r P | , b = | r B − r P | , {\displaystyle a=|\mathbf {r} _{A}-\mathbf {r} _{P}|,\quad b=|\mathbf {r} _{B}-\mathbf {r} _{P}|,} which are the distances from the fulcrum to the input point A and to the output point B , respectively. Now introduce

792-405: The lever equals the power out, and the ratio of output to input force is given by the ratio of the distances from the fulcrum to the points of application of these forces. This is known as the law of the lever . The mechanical advantage of a lever can be determined by considering the balance of moments or torque , T , about the fulcrum. If the distance traveled is greater, then the output force

825-486: The model of a pair of scissors . The name of the tool is derived from the verb "to lop ", meaning to cut off (especially branches or twigs), which in turn is related to a noun of precisely the same form: a "lop" is a period or session of branch cutting. The noun and verb first appeared in Middle English as loppe , but have no known antecedents or cognates in other languages. The main distinction among loppers

858-414: The next, and thus the applied force is transferred from one lever to the next. Examples of compound levers include scales, nail clippers and piano keys. The malleus , incus and stapes are small bones in the middle ear , connected as compound levers, that transfer sound waves from the eardrum to the oval window of the cochlea . The lever is a movable bar that pivots on a fulcrum attached to

891-562: The points A and B are obtained as v A = θ ˙ a e A ⊥ , v B = θ ˙ b e B ⊥ , {\displaystyle \mathbf {v} _{A}={\dot {\theta }}a\mathbf {e} _{A}^{\perp },\quad \mathbf {v} _{B}={\dot {\theta }}b\mathbf {e} _{B}^{\perp },} where e A and e B are unit vectors perpendicular to e A and e B , respectively. The angle θ

924-420: The pruning of tree branches with diameters less than 5 centimetres (2 in). Some of the newer lopper designs have a gear or compound lever system which increases the force applied to the blades, or a ratchet drive. The word lopper can be used in the singular or the plural, with precisely the same meaning. The plural form, most common in speech but less so in print, is a plurale tantum , and seems to be on

957-411: The pull of gravity) of both a and b change (diminish) as the lever changes to any position away from the horizontal. Levers are classified by the relative positions of the fulcrum, effort and resistance (or load). It is common to call the input force "effort" and the output force "load" or "resistance". This allows the identification of three classes of levers by the relative locations of the fulcrum,

990-424: The resistance and the effort: These cases are described by the mnemonic fre 123 where the f fulcrum is between r and e for the 1st class lever, the r resistance is between f and e for the 2nd class lever, and the e effort is between f and r for the 3rd class lever. A compound lever comprises several levers acting in series: the resistance from one lever in a system of levers acts as effort for

1023-550: The stem of the verb lever , meaning "to raise". The verb, in turn, goes back to Latin : levare , itself from the adjective levis , meaning "light" (as in "not heavy"). The word's primary origin is the Proto-Indo-European stem legwh- , meaning "light", "easy" or "nimble", among other things. The PIE stem also gave rise to the English word "light". The earliest evidence of the lever mechanism dates back to

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1056-448: The unit vectors e A and e B from the fulcrum to the point A and B , so r A − r P = a e A , r B − r P = b e B . {\displaystyle \mathbf {r} _{A}-\mathbf {r} _{P}=a\mathbf {e} _{A},\quad \mathbf {r} _{B}-\mathbf {r} _{P}=b\mathbf {e} _{B}.} The velocity of

1089-404: The world." Autumn Stanley argues that the digging stick can be considered the first lever, which would position prehistoric women as the inventors of lever technology. A lever is a beam connected to ground by a hinge, or pivot, called a fulcrum. The ideal lever does not dissipate or store energy, which means there is no friction in the hinge or bending in the beam. In this case, the power into

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