Solutions to Statics exam 2 practice problems.
 
Trusses
6.31   a) BC, CD, IJ, IL, LM, MN.   b) BC, BE, DE, EF, FG, IJ, KN, MN.
 
6.32   a) AI, BJ, CK, DI, EI, FK, GK.   b) FK, IO.
 
6.10   Fab=Ffh=1500lbC, Fac=Fce=Feg=Fgh=1200lbT, Fbc=Ffg=0; Fbd=Fdf=1200C; Fbe=Fef=60lb C; Fde=72lb T.
 
6.11  Fab=Ffg=11.08kN C; Fac=Feg=10.13kN T; Fbc=Fef=2.81kN C ; Fbd+Fdf+9.23kN C; Fcd=Fde=2.81kN T; Fce=g.75kN T
 
6.12   Fab=Fhi=12.31kN C; Fac=Fgi=11.25kN T; Fbc=Fgh=2.46kN C; Fbd=Fde=Fef=Ffh=9.85kN C; Fcd=Ffg=2.0kN C; Fce=Feg=3.75kN T; Fcg=6.75kNT
 
Frames/Machines
6.4 Ax=300N(left) Ay=480N(up), B=300N(right), Fde=561N T, Cx=795N , Cy=216N
 
6.5    F=1800N (up), Ex=0, Ey=600N (up), Ax=0, Ay= 1800N, Bx=0, By=1200N, Cx=0, Cy=3600.
 
6.6   Ex=1080lb <=, Ey=1000lb (down), Fx=480lb (down), Fy=1000lb (up), Fcd=1560 T
 
6.7   Fdh=5.15kN
 
Shear and Moment Diagrams
 
7.2 
Max V; 26kN @x=2.5-5.5m
Min V” –20 kN @ for 0<x<2.5m, –14kN for 5.5m<x<7.5m
Max M: 28kN @ x=5.5m
Min  M: –50kN m @ x=2.5 m
 
7.3 
Max V: 515lb @ x=0, 35lb @ 12” <x <18”,
Min V: –365lb @ 18”<x< 32”
Max M: 3300 lb in @x=12”, 3510 lb in @ x=18”, 5110 lb in @ x=18”
 
11.3 
Max V 1490lb@x=0, 1170lb@ x=4’, 900lb @ x=12’
Min V: –30lb @x=4’, -1330lb @ x=9’, –1870 @ x=12’
Max M: 5533 ft lb @ x=4’, 2550 ft lb @x=9’
Min M –2250 ft lb @ x=12’
 
Friction
10.1  a) The blocks are in equilibrium.  Ff=100N<Ffmax=120N
b) Block A slides down the ramp if cable is cut.
 
8.15  ø=31.08
 
8.16 ø=53.58
 
8.19 a) 36 lb, b) 36 lb, c) 12.86 lb
 
8.20  a) 36 lb, b) 40 in.