COLLEGE OF ENGINEERING

PUTRAJAYA CAMPUS

FINAL EXAMINATION

SEMESTER 1 2014 / 2015

PROGRAMME : BME/BEPE/BEEE/BCCE (Honours)

SUBJECT CODE : MEMB123 / MEMB214

SUBJECT : Mechanics I: Statics

DATE : September 2014

TIME : 3 hours

INSTRUCTIONS TO CANDIDATES:

1. This paper contains SIX (6) questions in EIGHT (8) pages.

2. Answer ALL questions.

3. Write ALL answers in the answer booklet provided.

4. Write answer to each question on a new page.

THIS QUESTION PAPER CONSISTS OF (8) PRINTED PAGES INCLUDING

THIS COVER PAGE.

Page 1 of 8

MEMB123/MEMB214, Semester 1 2014/2015

Page 2 of 8

QUESTION 1 (16 MARKS)

The members shown in Figure 1 are pin connected at A, D and F. The slotted

member DE is vertical and the weight of the suspended object is 223 N.

a) Draw the free body diagram of each member and explain the significance of

each force acting on the diagram. [4 marks]

b) Determine the tension in the spring and the reactions at F. [12 marks]

Figure 1

MEMB123/MEMB214, Semester 1 2014/2015

Page 3 of 8

QUESTION 2 (18 MARKS)

The pipe assembly is secured by two brackets on the wall as shown in Figure 2. The

frictional force of both brackets can resist a maximum moment of 350 Nm and the

flowerpot weighs of 47 kg.

a) Draw the free body diagram of the pipe assembly with the flower pot.

[7 marks]

b) Would the weight of the flowerpot cause the assembly to rotate about the OA

axis? Justify your answer. [11 marks]

Figure 2

MEMB123/MEMB214, Semester 1 2014/2015

Page 4 of 8

QUESTION 3 (16 MARKS)

a) What are the types of friction problems and compare them in terms of the number

of unknowns, available equilibrium equations, frictional equations and/or

conditional equations for tipping. [3 marks]

b) The 50-kg boy at A is suspended from the cable that passes over the quarter

circular cliff rock as shown in Figure 3.

(i) Determine if it is possible for the 92.5 kg woman to hoist him up. The

coefficient of static friction between the cable and the rock is μs = 0.2, and

between the shoes of the woman and the ground is μs’ = 0.8. [8 marks]

(ii) What horizontal force must the woman exert on the cable in order to let the

boy descend at a constant velocity, given that the coefficients of static and

kinetic friction between the cable and the rock are μs = 0.2 and μk = 0.15,

respectively. [5 marks]

Figure 3

MEMB123/MEMB214, Semester 1 2014/2015

Page 5 of 8

QUESTION 4 [17 MARKS]

The roof truss loaded as shown in Figure 4 is supported by a pin at A and roller at M.

a) Construct the free-body diagram of the roof truss. [4 marks]

b) Determine the support reactions at the pin A and roller M. [3 marks]

c) Determine the force in members HJ, GJ, and GI and state if these members

are in tension or compression. [10 marks]

Figure 4

MEMB123/MEMB214, Semester 1 2014/2015

Page 6 of 8

QUESTION 5 [18 MARKS]

The points D and E are in the overhang beam as shown in Figure 5. Point D is

located just to the left of the roller support at B, where the couple moment acts.

a) Draw the free body diagram for the beam AC, DC and EC. [9 marks]

b) Determine the internal normal force, shear force, and moment at points D and

E. [9 marks]

Figure 5

MEMB123/MEMB214, Semester 1 2014/2015

Page 7 of 8

QUESTION 6 [15 MARKS]

A simply supported structure is modelled as a shaded area as shown in Figure 6.

a) Locate the centroid x and y of the shaded area. [7 marks]

b) Determine the moment of inertia of the shaded area about the x-axis Ix.

[8 marks]

Figure 6

--- END OF QUESTION PAPER---

MEMB123/MEMB214, Semester 1 2014/2015

Page 8 of 8

Appendix

Table of Moment of Inertia