工程力学双语课件ch04-Resultant-of-non-concurrent-Forces-in-a-Plane

idealizedmodel)1.Rigidbodyisaspecialsystemofparticles,thedistancebetweenanytwoparticleswillnotchange.directions:2.Allrulesofsystemofparticlescanbeappliedtorigidbodywithasimplerform.4.2TransmissibilityAforcemaybetransmittedormovedtoanyotherpointonitslineofactionwithoutchangingtheeffectoftheforceontherigidbody.1、Thebodymustberigidbody,andnotbedeformablebody.2、Therigidbodymustbeoneonly,andnotbetwoormore.AAQ:what’sthelimitationsoftheprincipleoftransmissibility?4.2Transmissibility4.3Momentofaforce.4.3.1definitionofmomentofaforce.+-directionofmoment.4.3Momentofaforce.⑴isscalarquantity。(2)WhenF=0ord=0,=0。(3)=2⊿AOB=Fd。4.3.2Notingofmomentofaforce.4.4Theoremofmoment.4.4.1.Varignon’ponentsofthatforceaboutthesamepoint.4.4.2Example.Example4.1(P101).Example4.2(P102).Example4.3(P104).4.4Theoremofmoment.