Mechanics of Rigid Bodies
INSTRUCTIONS: Show a complete solution to each problem and box the final answers. Follow the format in Problem Sets. Submit before 12:00 PM
on Monday, January 22, 2024, in the CE Faculty Room.
SITUATION 1: Given the truss in the figure. Calculate the following:
1. Reaction at F.
A. 15 kN
C. 10 kN
B. 8 kN D. 12 kN
2. Reaction at C.
A. 15 kN
C. 17 kN
B. 8 kN D. 10 kN
3. Zero members.
A. BE and BD
B. BD and DF
C. BE, DE and DF
D. BE, BD and DE
SITUATION 2: A 200-N force is applied as shown in the bracket ABC.
4. Calculate component of moment about A parallel to x-axis.
A. 8 N-m
C. 13 N-m
B. 7.5 N-m
D. 12 N-m
5. Calculate component of moment about A parallel to y-axis.
A. 7.5 N-m
C. 8 N-m
B. 6 N-m
D. 9 N-m
6. Calculate component of moment about A parallel to z-axis.
A. 5.43 N-m
C. 10.39 N-m
B. 16.42 N-m
D. 11.23 N-m
SITUATION 3: A loading car is at rest on a track forming an angle of 25° with the vertical. The gross weight of the car and its load is 5500 lb, and it is
applied at a point 30 in. from the track, halfway between the two axles. The car is held by a cable attached 24 in. from the track.
7. Determine the tension in the cable.
A. 4980 lb
C. 3340 lb
B. 2320 lb
D. 3890 lb
8. Determine the reaction at the upper wheel.
A. 562 lb
C. 1230 lb
B. 1758 lb
D. 1190 lb
9. Determine the reaction at the lower wheel.
A. 562 lb
C. 1230 lb
B. 1758 lb
D. 1190 lb
10. The frame shown supports part of the roof of a small building. Knowing that the tension in the cable is 150 kN, determine the
moment reaction at the fixed end E in kN-m.
A. 200 C. 240
B. 150 D. 180
SITUATION 4: A 120 kg man walks on a 4 m plank resting on rough surfaces at A and B in the Figure MEECC-001. Given: 𝜇𝐴 = 0.40 and 𝜇𝐵 =
0.20.
Figure MEECC-001
11. At what distance x will the plank start to slide?
A. 2.32m
C.3.24m
B. 1.45m
D.2.65m
12. What is the friction force at A?
A. 234.12N
C.256.72N
B. 304.34N
D.100.43N
13. Find the vertical force at B.
A. 350N
C.493N
B. 212N
D.512N
SITUATION 5: The chisel exerts a force of 20 lb on the wood dowel rod which is turning in a lathe. See Figure 8BE24OK-2
14. Resolve the force into a component acting along y axes.
A. 14.1 lb
C.16.3 lb
B. 5.98 lb
D.22.3 lb
15. Resolve the force into a component acting along n axes.
A. 14.1 lb
C.16.3 lb
B. 5.98 lb
D.22.3 lb
16. Resolve the force into a component acting along x axes.
A. 14.1 lb
C.16.3 lb
B. 5.98 lb
D.22.3 lb
Figure 8BE24OK-2
SITUATION 6: If cable AB in Figure TMOTB-001 is subjected to a tension of 700 N.
Find the following:
17. Calculate the tension in cable AC.
A. 130 N
C.300 N
B. 140 N
D.255 N
18. Calculate the tension in cable AD.
A. 510 N
C.450 N
B. 630 N
D.600 N
19. Calculate the magnitude of the vertical force F.
A. 2300 N
C.1060 N
B. 5320 N
D.1500 N
Figure TMOTB-001
20. Consider the Warren truss shown in Figure WT-001. Determine the force in BC.
A. 30 k C.48 k
B. 64 k D.24 k
Figure WT-001