Summer Examinations 2015

Transcription

1 Summer Examinations 2015 ENG200115N Module Title Level Time Allowed Advanced Engineering Principles Five Two hours Instructions to students: Enter your student number not your name on all answer books. Answer two questions from Section A and two questions from Section B. All questions carry equal marks. Where a question has more than one part the division of marks is stated. Begin each answer in a separate answer book; label each book clearly with the number of the question you are answering. The use of a non-programmable scientific calculator is permitted. Graph paper and a formula booklet are provided. Students are permitted to remove this examination paper at the end of the examination. No. of Pages 7 No. of Questions 6 Page 1 of 7

2 Section A Answer two questions from this section. The segment of code shown in Table 1 (page 4) is written in 8086 Assembly Language. When running, it allows the user to input a lower case letter from the keyboard [a-z]. The program then displays the ASCII value of that character and the uppercase corresponding letter in binary format. The program does this task forever. An output example is shown below: Question 1 a. Describe how the binary number system can be used to represent unsigned integer numbers, using as an example the decimal number 352 expressed as a 16-bit binary number. (4 marks) b. Describe how the ASCII code represents the letters a and A using even and odd parity (see Table 2 on page 5). (6 marks) c. In the program in Table 1 (page 4) explain what each of lines 1 to 5 is doing and the purpose of these lines. d. Identify part of the program which is a subroutine and explain how it works. (8 marks) Question 2 a. Describe how hexadecimal notation is used to represent binary codes, using as an example the decimal value of -546 as a 16-bit numbers. b. Explain what is meant by a directive and give two examples from the program in Table 1 (page 4), with an explanation of what they do. (4 marks) c. In the program in Table 1 (page 4) explain what each of lines 25 and 26 are doing, and the overall purpose of these lines. (6 marks) d. Draw a flow chart of the program in Table 1 (page 4). Page 2 of 7 (8 marks)

3 Question 3 a. Explain the function of the stack in the context of subroutines. b. Explain how negative numbers can be represented in binary using 2 s complement, using as an example the decimal value 47 expressed as an 8-bit binary number. (6 marks) c. Explain what is meant by an interrupt and the lines 12, 13 and 14 in the program listed in Table 1 (page 4). d. What are lines 8 to 11 in the program in Table 1 (page 4) doing and how do they achieve their overall function? Page 3 of 7

4 Table Assembly Language program for Questions 1, 2 and 3 Line Labels Assembly Language Comments 00 ORG 100h 01 start: MOV AH,09h 02 MOV DX, OFFSET msg1 03 INT 21h ; interrupt 04 MOV AH,01h 05 INT 21h ; interrupt 06 MOV [Char_LC], AL ; store the lowercase 07 CALL print_bin 08 MOV BX, 32d 09 MOV AL,[Char_LC] 10 SUB AL, BL 11 MOV [Char_UC],AL Page 4 of 7 character ;print the ASCII value in binary ; store the new uppercase caharacter 12 MOV AH, 2 13 MOV DL,09h ; display a tabulator 14 INT 21h 15 MOV DL, [Char_UC] 16 INT 21h 17 MOV AL, [Char_UC] 18 CALL print_bin 19 JMP start 20 INT 20h 21 print_bin: MOV BL, AL ; subroutine 22 MOV CX, 8 23 bin_out: MOV AH, 2 24 MOV DL, '0' 25 TEST BL, b ; check MSB value 26 JZ zero 27 MOV DL, '1' 28 zero: INT 21h 29 SHL BL, 1 30 LOOP bin_out 31 MOV DL, 'b' 32 INT 21h 33 RET ; return from subroutine msg1 DB 0Dh,0Ah,"Type a lower case character [a-z]: $" 36 Char_LC DB 0 37 Char_UC DB 0

5 Table 2 The ASCII character set End of Section A Section B follows overleaf Page 5 of 7

6 Section B Answer two questions from this section. Question 4 Find the deflection of the beam shown in Fig. Q4 at the centre position. The flexural stiffness is 18 MNm 2. Fig. Q4 (25 marks) Question 5 A rectangular column of section 60 mm x 40 mm is subjected to a compressive load of 100 kn applied as shown in Fig. Q5. 60 Y B C Load point X 5 X 40 A D (All dimensions in mm). Y Fig. Q5 Calculate the magnitude and sense of the stresses at A, B, C and D. (25 marks) Page 6 of 7

7 Question 6 A pulley system uses a flat belt of cross- sectional area 800 mm2 and density 1200 kg/m3. The angle of lap is 160o on the smaller wheel. The coefficient of friction is 0.3. The maximum stress allowed in the belt is 3 N/mm2. a. Calculate: i. the belt speed for maximum power transmission. ii. iii. the maximum power transmittable by varying the speed. the initial belt tensions. b. Explain why the vee-belt is able to transmit more power than a flat belt. (10 marks) End of Paper Page 7 of 7