Carrucola

La carrucola è una macchina semplice adatta al sollevamento di carichi, costituita da una puleggia, funi (o cinghie) e cavi.

Nel lessico nautico viene chiamata bozzello.

Tipi di carrucole

Carrucola fissa

La carrucola fissa non si può considerare come una leva vera e propria, anche se possiede caratteristiche molto simili ad essa. Essa è conosciuta anche come macchina di Atwood.

Nella carrucola fissa, l'asse della puleggia è fissa, e la ruota ha una sola funzione cioè quella di deviare la forza applicata ad un'estremità della fune. Il vantaggio meccanico, se fosse nullo l'attrito nei perni e nella rigidità della fune, sarebbe pari ad uno (F = m).

In pratica il rapporto F/m è invece sempre superiore a 1 e deriva dal rendimento della carrucola (che è sempre minore di uno) e cioè:

dove:

ηc è il reciproco del rendimento della carrucola
(1 + 2μp d / D) è il reciproco del rendimento del perno (coppia rotoidale)
μ = coefficiente d'attrito della fune
μp è il coefficiente d'attrito del perno
D = diametro della carrucola
d = diametro del perno
D e d, nel dimensionare la carrucola dipendono da df, il diametro della fune, perciò in pratica ηc si fa dipendere da df.


Carrucola mobile

In questa categoria rientrano le carrucole nelle quali l'asse della puleggia è mobile solitamente e solidalmente con il carico sollevato. È una leva di 2° genere.

Carrucola composta

Una carrucola composta è un insieme di due o più carrucole fisse e mobili

I sistemi di carrucole multiple sono anche detti paranchi.

Questa macchina semplice è usata fin dai tempi antichi per amplificare enormemente la forza umana, per sollevare elementi architettonici, colonne, obelischi, trascinare blocchi di marmo, tirare navi in secca ecc...

Voci correlate

Altri progetti

Collegamenti esterni

Controllo di autoritàThesaurus BNCF 23039 · LCCN (EN) sh85108987 · BNF (FR) cb11980848q (data) · J9U (EN, HE) 987007548665605171
  Portale Fisica

Read other articles:

Aino Kishi

Aino KishiNama asal希志あいのLahir1 Februari 1988 (umur 36)Hokkaido, JepangKebangsaan JapanPekerjaanAktris Tahun aktif2008–2015Tinggi156 cm (5 ft 1 in)Situs webwww.duo-official.com/models/aino-kishi.htmTanda tangan Aino Kishi (希志あいのcode: ja is deprecated , Kishi Aino, lahir 1 Februari 1988),[1] adalah seorang aktris, penyanyi dan mantan AV idol asal Jepang. Kishi memulai karirnya pada tahun 2008, Kishi membintangi lebih dari 400 fil...

 

Saint-Joseph (Michigan)

Pour les articles homonymes, voir Saint-Joseph. Cet article est une ébauche concernant une localité du Michigan. Vous pouvez partager vos connaissances en l’améliorant (comment ?) selon les recommandations des projets correspondants. Saint-Joseph Administration Pays États-Unis État Michigan Comté Berrien Démographie Population 8 365 hab. (2010) Densité 697 hab./km2 Géographie Coordonnées 42° 05′ 53″ nord, 86° 29′ 03″ oue...

 

Nissan Terra

Nissan TerraNissan Terra saat dipamerkan di Auto Shanghai 2019.InformasiProdusenNissanMasa produksi2018–sekarangPerakitanTiongkok: ZhengzhouThailand: Samut PrakanBodi & rangkaKelasSUVBentuk kerangkaSUV 5 pintuTata letakFront-engine, rear-wheel-driveFront-engine, four-wheel-drivePlatformNissan F-Alpha platformMobil terkaitNissan NavaraPenyalur dayaMesin2.5 L QR25DE I4 (bensin)2.5 L YD25DDTi I4 (diesel)Daya keluar134 kW (180 hp; 182 PS) (bensin)140 ...

Cai Yong

Chinese official and scholar (132–192) In this Chinese name, the family name is Cai. Cai Yong蔡邕An illustration of Cai Yong in Sancai TuhuiLeft General of the Household(左中郎將)In office189 (189)–192 (192)MonarchEmperor Xian of HanChancellorDong Zhuo Personal detailsBorn132Qi County, Kaifeng, HenanDiedc.June 192 (aged 60)Xi'an, ShaanxiChildrenCai Yanat least one other daughterat least one sonParentCai Leng (father)RelativesCai Xi (grandfather)Cai Zhi (uncle)Yang Hu (gran...

 

Allophilie

L'allophilie est le fait d'avoir une attitude positive à l'égard d'un groupe qui n'est pas le sien. Le terme est dérivé de mots grecs signifiant « aimer ou adorer l'autre »[1]. C'est un cadre pour comprendre quantitativement le leadership intergroupe. Il est conceptualisé comme un état d'esprit mesurable, avec des conséquences tangibles[2],[3]. Le terme allophilie a été inventé par le professeur Todd L. Pittinsky de Harvard, en 2006, après avoir cherché en vain dans pl...

 

James Iredell

James Iredell Hakim Mahkamah Agung Amerika SerikatMasa jabatan12 Mei 1790 – 20 Oktober 1799 Informasi pribadiKebangsaanAmerika SerikatProfesiHakimSunting kotak info • L • B James Iredell adalah hakim Mahkamah Agung Amerika Serikat. Ia mulai menjabat sebagai hakim pada mahkamah tersebut pada tanggal 12 Mei 1790. Masa baktinya sebagai hakim berakhir pada tanggal 20 Oktober 1799.[1] Referensi ^ Justices 1789 to Present. Washington, D.C.: Mahkamah Agung Amerika Se...

E. B. Ficklen House

Historic house in North Carolina, United States United States historic placeE. B. Ficklen HouseU.S. National Register of Historic PlacesU.S. Historic districtContributing property E. B. Ficklen House, September 2014Show map of North CarolinaShow map of the United StatesLocation508 W. 5th St., Greenville, North CarolinaCoordinates35°36′45″N 77°22′47″W / 35.61250°N 77.37972°W / 35.61250; -77.37972Area1.2 acres (0.49 ha)Built1902 (1902)Architectural&...

 

俄亥俄州

  「俄亥俄」重定向至此。关于其他用法，请见「俄亥俄 (消歧义)」。 俄亥俄州 美國联邦州State of Ohio 州旗州徽綽號：七葉果之州地图中高亮部分为俄亥俄州坐标：38°27'N－41°58'N, 80°32'W－84°49'W国家 美國加入聯邦1803年3月1日，在1953年8月7日追溯頒定（第17个加入联邦）首府哥倫布（及最大城市）政府 • 州长（英语：List of Governors of {{{Name}}}]]） •&...

 

美国众议院

此條目需要补充更多来源。 (2021年7月4日)请协助補充多方面可靠来源以改善这篇条目，无法查证的内容可能會因為异议提出而被移除。致使用者：请搜索一下条目的标题（来源搜索：美国众议院 — 网页、新闻、书籍、学术、图像），以检查网络上是否存在该主题的更多可靠来源（判定指引）。 美國眾議院 United States House of Representatives第118届美国国会众议院徽章 众议院旗...

Value of Earth

An economical concept of estimating the net worth of the planet Part of a series aboutEnvironmental economics Carbon price Carbon credit Carbon emission trading Carbon fee and dividend Carbon finance Carbon offset Carbon tax Emissions trading Environmental tax Personal carbon trading Pigovian tax Social cost of carbon Climate change Carbon footprint Climate change mitigation Food miles Concepts Bright green environmentalism Circular economy Climate finance Corporate sustainability Degrowth Di...

 

哈萨克斯坦总统

此条目序言章节没有充分总结全文内容要点。 (2019年3月21日)请考虑扩充序言，清晰概述条目所有重點。请在条目的讨论页讨论此问题。 哈萨克斯坦總統哈薩克總統旗現任Қасым-Жомарт Кемелұлы Тоқаев卡瑟姆若马尔特·托卡耶夫自2019年3月20日在任任期7年首任努尔苏丹·纳扎尔巴耶夫设立1990年4月24日（哈薩克蘇維埃社會主義共和國總統） 哈萨克斯坦 哈萨克斯坦政府...

 

Earl Cooper

American racing driver (1886–1965) This article is about the American auto racer. For the NFL player, see Earl Cooper (American football). Earl CooperCooper (left) and Barney Oldfield with their wives in 1926BornEarl Phillips Cooper(1886-12-02)December 2, 1886Broken Bow, Nebraska, U.S.DiedOctober 22, 1965(1965-10-22) (aged 78)Atwater, California, U.S.Champ Car career89 races run over 16 yearsBest finish2nd (1924)First race1911 Oakland Trophy (Portola)Last race1927 75-mile Race (Rocking...

M. K. Indira

Indian writer M. K. IndiraBornMandagadde Krishnarao Indira(1917-01-05)5 January 1917Thirthahalli, Kingdom of Mysore, British IndiaDied15 March 1994(1994-03-15) (aged 77)OccupationWriterNationalityIndianNotable worksPhaniyamma, Gejje PoojeSpouseKrishna Rao Mandagadde Krishnarao Indira (Kannada: ಮಂಡಗದ್ದೆ ಕೃಷ್ಣರಾವ್ ಇಂದಿರ; 5 January 1917 – 15 March 1994) was a well-known Indian novelist in the Kannada language. Her works include Phaniyamma, w...

 

Biogenic substance

Product made by or of life forms Crude oil, a transformed biogenic substance Natural gum, a secretion from Hevea brasiliensis A biogenic substance is a product made by or of life forms. While the term originally was specific to metabolite compounds that had toxic effects on other organisms,[1] it has developed to encompass any constituents, secretions, and metabolites of plants or animals.[2] In context of molecular biology, biogenic substances are referred to as biomolecules....

 

العلاقات الدنماركية السريلانكية

العلاقات الدنماركية السريلانكية الدنمارك سريلانكا   الدنمارك   سريلانكا تعديل مصدري - تعديل   العلاقات الدنماركية السريلانكية هي العلاقات الثنائية التي تجمع بين الدنمارك وسريلانكا.[1][2][3][4][5] مقارنة بين البلدين هذه مقارنة عامة ومرجعية لل�...

5 Years in a Livetime

5 Years in a LIVEtimeVideo karya Dream TheaterDirilis27 Oktober 1998DirekamVariousGenreProgressive metal, progressive rockLabelEastWest RecordsKronologi Dream Theater Images and Words: Live in Tokyo(1993)Images and Words: Live in Tokyo1993 5 Years in a LIVEtime (1998) Metropolis 2000: Scenes from New York(2001)Metropolis 2000: Scenes from New York2001 Penilaian profesional Skor ulasan Sumber Nilai Allmusic [1] 5 Years in a LIVEtime adalah rilis video kedua oleh Dream Theater. Vide...

 

Chiesa di Santa Brigida (Santa Brigida)

Chiesa di Santa BrigidaStato Italia RegioneLombardia LocalitàSanta Brigida Coordinate45°58′56.37″N 9°37′30.23″E45°58′56.37″N, 9°37′30.23″E ReligioneCristiana cattolica di rito ambrosiano TitolareSanta Brigida d'Irlanda Diocesi Bergamo Consacrazione1925 ArchitettoLuigi Angelini Stile architettoniconeoromanico Inizio costruzione1919 Modifica dati su Wikidata · Manuale La chiesa di Santa Brigida è la parrocchiale di Santa Brigida, in provincia e diocesi di Bergam...

 

Batman Forever (soundtrack)

For the Elliot Goldenthal musical score, see Batman Forever (score). 1995 soundtrack album by various artistsBatman Forever: Music from the Motion PictureSoundtrack album by various artistsReleasedMay 30, 1995[1]RecordedSeptember 1994−March 1995Length59:28LabelAtlanticProducerJolene Cherry (ex.)Joel Schumacher (ex.)Gary LeMel (ex.)Nellee HooperBonoThe EdgeFloodPJ HarveyJohn ParishLenny KravitzTrevor HornMassive AttackThe Insects (add.)Neil Davidge (add.)David RobackThom Wils...

Seo Ha-joon

Ini adalah nama Korea; marganya adalah Seo. Seo Ha-joonGaon Chart K-POP Award Red Carpet, 2016Lahir19 September 1989 (umur 34)Seoul, Korea SelatanPekerjaanAktorTahun aktif2013-sekarangAgenSH EntertainmentNama KoreaHangul서하준 Alih AksaraSeo Ha-junMcCune–ReischauerSŏ Ha-chun Seo Ha-joon (lahir 19 September 1989) adalah aktor asal Korea Selatan.[1][2][3] Filmografi Serial televisi Tahun Judul Peran Jaringan 2013 Princess Aurora Seol Seol-hee MBC 2014 Onl...

 

Skipjack (bateau)

Le skipjack Minnie V sous voile Le skipjack est un bateau ostréicole de pêche traditionnelle utilisé dans la baie de Chesapeake pour le dragage des huîtres. C'est un voilier qui a succédé au type bugeye en tant que principal bateau ostréicole sur la baie, et il reste en service en raison des lois restreignant l'utilisation du bateau à moteur pour la pêche aux huîtres de l'État du Maryland. Conception et construction Ce voilier de pêche est gréé en sloop, avec un mât fortement i...