Name: net moment sign convention in 2d forces
Uploaded: 2023-09-22T11:49:20.000Z
Duration: 1 min 31 s
Channel: JoVE

Rozważmy belkę wspornikową, na którą działają siły 1000 N, 600 N, 750 N i 500 N w różnych punktach odpowiednio B, C, D i E. Moment generowany w punkcie A przez określoną siłę jest iloczynem jednej z sił o odpowiedniej prostopadłej odległości od punktu przyłożenia siły do punktu stałego A.
Tutaj siły F1, F2 i F3 generują moment w kierunku zgodnym z ruchem wskazówek zegara, który jest konwencjonalnie uważany za ujemny, podczas gdy moment wytwarzany przez siłę F4 jest dodatni biorąc pod uwagę kierunek przeciwny do ruchu wskazówek zegara.
Moment wypadkowy wywołany przez wszystkie cztery siły jest obliczany jako algebraiczna suma wszystkich momentów generowanych przez każdą siłę w układzie.
Tutaj, ponieważ wielkość momentu wynikowego jest ujemna, działa on w kierunku zgodnym z ruchem wskazówek zegara.
Załóżmy teraz, że kierunek siły F3 jest odwrócony. Moment wynikowy będzie dodatni, wskazując moment przeciwny do ruchu wskazówek zegara wokół punktu A.

<ol>
	<li>Hibbeler, R.C. (2016). Mechanika inżynierska \u2012 Statyka i dynamika. Hoboken, New Jersey: Pearson Prentice Hall. Strona 122.</li>
</ol>

moment wynikowy: rachunek skalarny

Resultant Moment: Scalar Formulation

Kiedy wiele sił działa na obiekt w przestrzeni dwuwymiarowej, pojęcie momentu netto może być użyteczne do zrozumienia tendencji tych sił do indukowania ruchu obrotowego wokół ustalonego punktu. Skalarna interpretacja momentu wynikowego jest pomocnym narzędziem do analizy równowagi struktur poddanych działaniu wielu sił.

Aby obliczyć moment wynikowy, uwzględnia się momenty spowodowane przez wszystkie siły w układzie na płaszczyźnie x-y . Momenty dodatnie są zwykle przeciwnie do ruchu wskazówek zegara, ponieważ są skierowane wzdłuż osi z, podczas gdy momenty ujemne są zgodnie z ruchem wskazówek zegara. Każdemu momentowi przypisuje się znak zgodnie z jego kierunkiem. Aby obliczyć moment wynikowy z powodu wszystkich sił, sumuje się iloczyny każdej siły i jej odpowiedniej odległości prostopadłej od danego punktu A.

<img alt="Equation 1" src="/files/ftp_upload/14252/14252_Equation_1v3.svg" style="text-align: center; height: 15px;" />

Konwencje znakowe dla momentów są używane w obliczeniach. Po podstawieniu wartości wszystkich sił i ich odległości prostopadłych do powyższego równania, jeżeli wynik numeryczny tego równania jest dodatni, to moment wynikowy będzie przeciwny do ruchu wskazówek zegara. W przeciwnym razie, jeżeli wynik jest ujemny, moment wynikowy będzie zgodny z ruchem wskazówek zegara.

Moment wynikowy: rachunek skalarny

Gdy na obiekt w przestrzeni dwuwymiarowej działa wiele sił, pojęcie momentu wypadkowego można wykorzystać do zrozumienia tendencji tych sił do ...

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Mechanical Engineering

Inżynieria mechaniczna

Unit 1

Jednostka 1

Force System Resultants

wypadkowe układu sił

KEY TERMS AND CONCEPTS

Kluczowe terminy i pojęcia

net moment sign convention in 2d forces

Net moment in two-dimensional force systems shows how multiple forces can cause rotation about a fixed point. The scalar formulation helps analyze equilibrium in structures that are acted on by several forces. It focuses on the x-y plane and uses a simple sign rule to describe the direction of rotation.

To find the resultant moment, the moments from all forces in the system are considered about a chosen point A. Each moment is assigned a sign based on its sense of rotation. Positive moments are usually counterclockwise and point along the positive z-axis. Negative moments are clockwise.

The calculation uses the algebraic sum of each force multiplied by its perpendicular distance from point A. This sign convention makes it possible to combine the effects of all the forces into one scalar value. If the final result is positive, the resultant moment is counterclockwise. If the result is negative, the resultant moment is clockwise.

Net Moment Sign Convention in 2D Forces

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key terms and concepts

Learn how to use the scalar form of net moment in 2D force systems. See how sign convention, perpendicular distance, and rotation direction determine the result.

Net Moment Sign Convention in 2D Forces | JoVE K12

JoVE Core Mechanical Engineering offers concise, easy-to-understand animated videos covering key topics such as equilibrium, forces, truss analysis, and structural mechanics. Explore their real-world applications, and witness these concepts in action through scientist-led experiments.

mechanical engineering

Net Moment Sign Convention in 2D Forces

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