PowerPoint PresentationHomework #9Last LectureEquilibrium EquationsSlide 5Slide 6Solving Equilibrium EquationsStatically Indeterminate ReactionsEquilibrium Example ProblemsME 221 Lecture 25 1ME 221 StaticsLecture #25Sections 5.1 – 5.7ME 221 Lecture 25 2Homework #9Chapter 5 problems:–54, 56, 62, 64, 69, 71 & 73•Due Wednesday, November 6ME 221 Lecture 25 3Last Lecture•Equilibrium in 3 Dimensions•Statically Indeterminate ReactionsME 221 Lecture 25 4Equilibrium 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 ME 221 Lecture 25 5Equilibrium 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&0Fo 0C)Fxr(Where the couple C is the sum of all applied couples on the bodyME 221 Lecture 25 6Equilibrium EquationsIf there are more than 6 unknown forces or couples, the problem is statically indeterminate.ME 221 Lecture 25 7Solving 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 unknownsME 221 Lecture 25 8Statically Indeterminate ReactionsUnderconstrained systemCannot maintain equilibriumOverconstrained systemsMore unknown forces than equationsME 221 Lecture 25 9Equilibrium Example
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