CARAGA STATE UNIVERSITY
CABADBARANCAMPUS
                                 T.Curato St.,Cabadbaran City, Philippines
                                     Tel. Nos. (085)3431020 / 281-2032
                                         csucc.carsu.edu.ph
                COLLEGE OF ENGINEERING AND INFORMATION TECHNOLOGY
                                                                                                       DAVE
JOSHUA N. BARORO                                                             Statics of Rigid Bodies
BSEE III - 8                                                                 Comprehensive Examination
                                                      Part 1:
    1.   Dynamics
    2.   Statics
    3.   Particle
    4.   Rigid bodies
    5.   Concentrated force
    6.   Scalar
    7.   Vector
    8.   Free Body Diagram
                                                 Part 2:
    1. First Law  at rest, having a constant velocity tends to remain in this state provided the
       particle is not subjected to an unbalanced load.
         Second Law  unbalanced force experiences an accelaration has same direction as the
         force and magnitude that is directly proportional to the force.
         Third Law  the mutual force of action between two particles are equal, opposite and
         collinear.
    2. Equilibrium- is the condition of a system in which all competing influences are balanced.
                      Part 3:
                 Problem #1
           Using triangle method:
               = 180 - 60 - 45
  FR = 4002 + 2502 -2(400)(250)(cos75)
                FR = 413.20 N
            sin                sin 75
            400
                       =        413.20
                  = 35.760
             = 60 - 35.76 = 24.240
                 Problem #2
            S1 = 22 + 1.52 = 2.5 m
              S2 = 22 + 22 = 22 m
                    F = sk
                = (22 - 2.5)(100)
                  F = 32.84 N
                           2
             = tan   (    2    ) = 45   0
Fy = 0         let W  weight of a cylinder
            2(32.84)(sin45) - 2W = 0
                  W = 23.22 N
          The mass of a cylinder (M)
                23.22 N
      M=       9.81m/ s 2        = 2.37 kg
                 Problem #3
                   FAB = FAB i
                     FAC = -FAC j
                              (20) i+(20) j+(10)k
         FAD = FAD   (       (2  0) 2+(2  0)2+(1  0) 2
                         2                2            1
           FAD = -       3     FADi +     3 FADj + +   3 FADk
                              W = [-m(9.81)k]
                                  Since,
                              F = 0
                          FAB + FAC + FAD - W = 0
                      2             2            1
FABi + (-FACj) + (-       FADi +        FADj + +    F k) + [-m(9.81)k]
                      3            3             3 AD
               2                      2           1
      (FAB -        F )i + (-FAC +       F )+(      F - 9.81m)k
               3 AD                  3 AD         3 AD
                         By i, j and k components:
                                     2
                              FAB -      F =0
                                     3 AD
                                       2
                               FAC +      F =0
                                      3 AD
                               1
                                   F - 9.81m = 0
                               3 AD
        Since the FAD = 0, then the mass of the crate is:
                             1
                               (3000) - 9.81m = 0
                             3
                                m = 101.94 kg
                                 Problem #4
                                      Joint C:
                                 +Fy = 0
                              sin30(FCB) - 1.5 = 0
                                 FCB = 3 kN (T)
                                 +Fx = 0
                               FCD + 3(cos30) = 0
                             FCD = -2.6 = 2.6 kN (C)
                                  Joint D:
                                  +Fx = 0
                                  FDE  2 = 0
                                 FDE = 2 kN (T)
         +Fy = 0
          FDB + 2.6 = 0
    FDB = -2.6 = 2.6 kN (C)
           Joint B:
          +Fy = 0
  FBE(cos30) + 2(cos30) = 0
      FBE = -2 = 2 kN (C)
       +Fx = 0
    (2+2)(sin30) + 3 FBA
       FDB = 5 kN (T)
       Problem #5
        +Fx = 0
        400  Ax = 0
         Ax = 400 N
         MC = 0
1200(8) + 400(3)  Dy(12) = 0
         Dy = 900 N
        +Fy = 0
      Ay -1200 +900 = 0
          Ay = 300 N
        At point G:
          MG = 0
  -300(4)  400(3) FBC(3) = 0
        FBC = 800 (T)
        At point C:
          MC = 0
     300(8) +FGE(3) = 0
  FGE = -800 N = 800 N (C)
        +Fy = 0
              3
     300  ( 5 )FGC = 0
        FGC 500 N (T)
       Problem #6
      At member AC:
                 MA = 0
-Cx(1.5sin60) + Cy(1.5cos60) + 600(0.75) = 0
             At member CB:
                 MB = 0
         -500(1) + Cx(1) + Cy(1) = 0
               Therefore:
               Cx = 402.63 N
               Cy = 97.37 N
             At member AC:
               +Fx = 0
       -Ax + 600(sin60)  402.63 = 0
                Ax = 117 N
              +Fy = 0
       Ay  600(cos60)  97.37 = 0
              Ay = 397.37 N
             At member CB:
               +Fx = 0
           402.63  500 + Bx = 0
               Bx = 97.37 N
                +Fy = 0
               -By +97.37 = 0
                 By = 97.37 N
               Problem #7
           Fy = 2T - 700 = 0
                 T = 350 lb
             Member ABC:
                    MA = 0
  By(4) - 700(8) - 100(4) - (350sin60)(4) = 0
               By = 1803.11 lb
                Fy = 0
   -Ay - 350sin60 -100 -700 + 1803.11 = 0
                 Ay = 700 lb
                 Fx = 0
      Ax - 350cos60 - Bx + 350 - 350 = 0
               Ax - Bx = 175 lb
     Member DB:
          MD = 0
-40(2) - 1803.11(4) + Bx = 0
      Bx = 1823.11 lb
        Fx = 0
     -Dx + 1823.11 = 0
      Dx + 1823.11 lb
        FY = 0
   Dy - 40  1803.11 = 0
     Dy = 1843.11 lb
 Since, Ax - Bx = 175
   Ax = 175 + 1823.11
     Ax = 1998.11 lb
     Problem #8
     Problem #9