PowerPoint PresentationHomework #5Quiz #5Exam #2Chapter 5 Equilibrium of Rigid BodiesLast LectureTodayEquilibrium EquationsSlide 9Slide 10Solving Equilibrium EquationsStatically Indeterminate ReactionsExampleSlide 14ME221 Lecture 12 1ME 221 StaticsLecture #12Sections 5.6 – 5.7ME221 Lecture 12 2Homework #5•Chapter 9 problem:–43•Chapter 5 problems–11, 20, 56 & 69–Due Monday, June 21•MatLab Group Problems–5.22, 5.37 & 5.58 –Due Monday, June 21ME221 Lecture 12 3Quiz #5TodayME221 Lecture 12 4Exam #2Monday, June 21ME221 Lecture 12 5Chapter 5Equilibrium of Rigid BodiesME221 Lecture 12 6Last Lecture•Equilibrium equations•Free body diagrams•2- & 3-force members•Modeling supportsME221 Lecture 12 7Today•Equilibrium in 3 Dimensions•Statically Indeterminate ReactionsME221 Lecture 12 8Equilibrium EquationsWe have examined 2-dimensional systems and analyzed their equilibrium conditions using the following:~ ~0 and 0F M The equilibrium conditions we used may be expressed as:0 00 00 0x xy yz zF MF MF M ME221 Lecture 12 9Equilibrium EquationsFor 3-dimensional systems, we use the same equilibrium equations, except we write them in vector form:The moment equation may also be written as: 0M & 0F oWhere the couple C is the sum of all applied couples on the body 0C )F x r(ME221 Lecture 12 10Equilibrium EquationsIf there are more than 6 unknown forces or couples, the problem is statically indeterminate.ME221 Lecture 12 11Solving Equilibrium EquationsDraw a proper free body diagramWrite each force and couple as a vectorDraw position vectors from the origin to the line of action of each force Write the vector equations of static equilibrium – 6 equations, 6 unknownsME221 Lecture 12 12Statically Indeterminate ReactionsUnderconstrained systemCannot maintain equilibriumOverconstrained systemsMore unknown forces than equationsME221 Lecture 12 13ExampleME221 Lecture 12 14Quiz
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