Yintoni Umsebenzi Wokwenyama?

NguSteven Holzner

Kwi-physics, umsebenzi wezandla ichazwa njengombutho osetyenzisiweyo ophindaphindiweyo licandelo lokufuduka eli kwicala elinye namandla. Ke ukuba ucofa ifriji eyi-2.0 m ukuya emgangathweni, kwaye kufuneka ufake i-900 N, wenze lo msebenzi ungaka:



(900) (2.0) = 1,800



1,800 yintoni? Umsebenzi kwinkqubo ye-MKS ulinganiswa ngee-joules, J, yiyo loo nto ili-1,800 J. Uyakuhlala ubona umsebenzi ochazwe kwiijoules kwiingxaki ze-physics. Icandelo le-CGS lomsebenzi yi (erdly named) erg, kodwa kunqabile ukuba uyibone isetyenzisiwe. (Icandelo le-FPS lomsebenzi yiponti yeenyawo.)

isiraphu yokukhwehlela ye-cherry tussin

Ke ukusebenzisa amandla ka-1.0 N kumgama we-1.0 m kuthetha ukuba wenze i-joule enye yomsebenzi. 1.0 J = 1.0 x 107I-ergs kuba ii-ergs ziisentimitha ezi-dyne, kwaye kukho i-105Iidynes ngeNewton kunye ne-10Mbiniiisentimitha kwimitha.



Kodwa umsebenzi awuphelelanga kumandla apheleleyo asetyenzisiweyo uphindaphindwe ngumgama ohanjiweyo; Into ekuphela kwayo kumandla abalulekileyo yile isetyenzisiweyo kwicala lokuhamba. Umzekelo, jonga ubunzima obutsaliwe kulo mzobo ulandelayo.

umfanekiso0.jpg

Amandla asetyenzisiweyo kwicala lokuhamba yeyona nto ibalulekileyo, ke ufuna icandelo F Ethe tye (ucinga ukuba urhuqa ubunzima kwaye awukhethi!). Eli candelo lithe tye F cos theta, ke umsebenzi owenzayo, NGAPHAKATHI , Ingaba yi:



umfanekiso1.png

Apha, F ngamandla asetyenziswayo, s kukufuduka, kwaye i-theta yikona phakathi kwabo.

Umzekelo wesampulu

  1. Cinga ukuba utsala ubunzima emfanekisweni ngokusebenzisa i-200. N kunye ne-angle theta ngama-40.0 degrees. Mngakanani umsebenzi owenzayo wokurhuqa ubunzima obungaphezu kwe-50.0 m?

    Impendulo echanekileyo ngu-7, 660 J.

    1. Sebenzisa le nxaki

      umfanekiso2.png

    2. Xhuma amanani:

      umfanekiso3.png

      xanax, yenzelwe ntoni?

Qhelisela imibuzo

  1. Utsala isifuba sedrawer, usebenzisa amandla angama-60.0 N kwi-angle ye-60.0 degrees. Wenza kangakanani umsebenzi wokutsala ngaphezulu kwe-10.0 m?

  2. Utsala isilingi ngentambo kwiidigri ezingama-30, usebenzisa amandla angama-20 N. Wenza umsebenzi ongakanani ngaphezulu kwe-1.0 km?

  3. 3. Utyhala ibhokisi yezitya ngapha komgangatho wekhitshi, usebenzisa i-100.0 J ukuyihambisa nge-10.0 m. Ukuba usebenzisa amandla kwi-60.0 degrees, yintoni amandla owasebenzisileyo?

  4. Utyhala imoto engaphandle kwerhasi apha endleleni, usebenzisa amandla ayi-800.0 N. Mngakanani umsebenzi owenzileyo wokuhambisa imoto nge-10.0 m?

Ezi zilandelayo ziimpendulo zemibuzo yokuziqhelanisa:

  1. Ngama-300 J

    1. Sebenzisa le nxaki

      mnyama mnyama ulusu ngokujikeleza umlomo

      umfanekiso4.png

    2. Xhuma amanani:

      umfanekiso5.png

  2. 1.7 x 104UJ

    1. Sebenzisa le nxaki

      umfanekiso6.png

    2. Xhuma amanani:

      umfanekiso7.png

  3. 20 N

    1. Sebenzisa le nxaki

      umfanekiso8.png

      ipilisi emhlophe embhoxo emhlophe
    2. Sombulula ngamandla:

      umfanekiso9.jpg

    3. Xhuma amanani:

      umfanekiso10.jpg

  4. Ama-8,000 uJ

    1. Sebenzisa le nxaki

      umfanekiso11.png

    2. Xhuma amanani:

      umfanekiso12.png