EGB102 Practice Exam PDF

Student Number Student's Name Practice Examination Paper SEMESTER: FIRST SEMESTER EXAMINATIONS (PRACTICE) UNIT: EGB102 FUNDAMENTALS OF ENGINEERING SCIENCE WORKING TIME:...

Student Number Student's Name Practice Examination Paper SEMESTER: FIRST SEMESTER EXAMINATIONS (PRACTICE) UNIT: EGB102 FUNDAMENTALS OF ENGINEERING SCIENCE WORKING TIME: 2 ½ Hours PERUSAL TIME: 10 Minutes EXAMINATION MATERIAL SUPPLIED BY THE UNIVERSITY: MARK SENSE ANSWER SHEET EXAMINATION BOOKLET (FOR WORKING ONLY) DATA AND FORMULAE SHEETS EXAMINATION MATERIAL SUPPLIED BY THE STUDENT: WRITING IMPLEMENTS - PENCILS, ERASER, BLUE OR BLACK PEN CALCULATORS - ANY SILENT TYPE (programmable calculators may be reset) INSTRUCTIONS TO STUDENT: Notes may be made on the examination paper during perusal time (unless this is a 'multiple choice' type examination paper). However, writing is not permitted on examination booklets, drawing paper, graph paper etc until such time as the Supervisor so authorises. ALL QUESTIONS ARE TO BE ANSWERED ON THE MULTIPLE CHOICE ANSWER SHEET PROVIDED. AN EXAMINATION BOOKLET IS PROVIDED FOR YOUR WORKING, HOWEVER NO WORKING WILL BE CONSIDERED IN ASSESSING THIS EXAMINATION. NO EXAMINATION MATERIALS (QUESTIONS OR ANSWER SHEETS OR WORKING PAPER) ARE TO BE REMOVED FROM THE EXAMINATION ROOM. © Queensland University of Technology  1 Multiple-choice questions All thirty-four (34) questions are to be attempted on the mark sense sheet provided All questions are of equal value Only one (1) answer is correct for each question Questions 1 to 5 refer to the following information: A 800 kg car is travelling forwards at + 25 m s−1 along a level road. The brake is suddenly applied, and the car skids to a stop leaving skid marks 75 m long. QUESTION 1 The acceleration (assumed constant) during skidding will be closest to (a) 0.2 m s−2 (b) 8.3 m s−2 (c) −4.2 m s−2 (d) −8.3 m s−2 QUESTION 2 The shape of the DISPLACEMENT (s) versus time (t) graph for this process will be closest to s (a) t s (b) t s (c) t s (d) t s (e) t EGB102T1.PRACTICE cont/…  2 QUESTION 3 During braking, which of the following statements will be true? (a) The net force on the car is unbalanced. (b) The frictional force of the car on the ground is directed forwards. (c) There are no forces on the car which are directed forwards. (d) All of these are true. QUESTION 4 Which of the following pairs of forces represents an action-reaction pair? (a) The weight of the car and the force of gravity exerted by the car on the earth. (b) The weight of the car and the normal force of the car on the road. (c) The weight of the car and the normal force of the road on the car. (d) All of these are action-reaction pairs. QUESTION 5 The magnitude of the work done by friction in bringing the car to a stop will be (a) 6.7 kJ (b) 588 kJ (c) 250 kJ (d) 3.3 kJ (e) unable to be calculated without the coefficient of friction. QUESTION 6 A skydiver has her parachute open and gently falls straight down to earth at a constant velocity for 30 seconds. Which one of the following statements is true for these 30 seconds? (a) The difference between the gravitational force and air resistance is responsible for the downward velocity. (b) Only the vertical forces acting on the skydiver are unbalanced. (c) All the forces on the skydiver are balanced. (d) Only the horizontal forces acting on the sky diver are unbalanced. (e) None of the above is true. EGB102T1.PRACTICE cont/…  3 Questions 7 and 8 refer to the following information: An expensive sports car of mass 900 kg is travelling at a speed of 30 ms-1 when it collides unexpectedly with a stationary industrial waste bin of mass 150 kg. The waste bin becomes lodged in the front of the car. QUESTION 7 Which of the following statements about the collision will be true? (a) There will be no kinetic energy in the system after the collision. (b) The collision is completely inelastic. (c) Momentum will not be conserved during the collision. (d) All of these are true. QUESTION 8 The velocity of the car and bin immediately after impact is closest to (a) 4.3 ms-1 (b) 26 ms-1 (c) 771 ms-1 (d) 28 ms-1 QUESTION 9 An object is attached to a hanging unstretched, ideal and massless spring and slowly lowered to its equilibrium position, a distance of 5.3 cm below the starting point. If instead of having been lowered slowly the object was dropped from rest, how far would it then stretch the spring at maximum elongation (measured from the point it was dropped)? (a) 21 cm (b) 5.3 cm (c) 15 cm (d) 7.5 cm (e) 11 cm QUESTION 10 A spring is placed in a vertical position with its lower end supported by a horizontal surface. A stone of mass 4.0 kg is rested on the spring and compresses the spring by 0.02 m. The same spring is then placed horizontally and used to launch the stone along the smooth horizontal surface. The spring is compressed by 0.08 m by the stone and then the spring is suddenly released. The speed at which the stone leaves the spring is closest to (a) 1.8 ms-1 (b) 2.5 ms-1 (c) 6.3 ms-1 (d) 3.1 ms-1 EGB102T1.PRACTICE cont/…  4 Questions 11 to 13 refer to the following information: 300 10 m 8.77 m Figure 1. A ball is projected from a 10 m high vertical building at an angle of 30 above the horizontal and hits the ground a horizontal distance of 8.77 m from the base of the building after 1.75 seconds. Assume that air resistance is negligible. QUESTION 11 Which one of the following statements about the horizontal motion of the ball is true? (a) The horizontal velocity of the ball will be 5 ms-1. (b) The horizontal acceleration of the ball will be zero. (c) The horizontal velocity at any time during will equal the initial horizontal velocity. (d) All of these are true. QUESTION 12 The initial speed of the ball will be closest to (a) 4 m s-1 (b) 5 m s-1 (c) 6 m s-1 (d) 10 m s-1 QUESTION 13 Just at the instant before the ball strikes the ground, the magnitude of the vertical component of the velocity will be closest to (a) 200 m s-1 (b) 14.3 m s-1 (c) 20.1 m s-1 (d) 14.6 m s-1 EGB102T1.PRACTICE cont/…  5 QUESTION 14 An aircraft performs a manoeuvre called an "aileron roll." During this manoeuvre, the plane turns like a screw as it maintains a straight flight path at a constant speed, which sets the wings in circular motion. If it takes it 37 s to complete the circle and the wingspan of the plane is 12.4 m, what is the acceleration of the wing tip? (a) 2.2 ms-2 (b) 5.6 ms-2 (c) 0.18 ms-2 (d) 0.45 ms-2 (e) The motion is not circular, therefore this acceleration cannot be easily calculated. QUESTION 15 A 1.0 kg block and a 2.0 kg block are pressed together on a horizontal frictionless surface with a compressed very light spring between them. They are not attached to the spring. After they are released and have both moved free of the spring, which one of the following statements is true? (a) Both blocks will have equal speeds. (b) The lighter block will have more kinetic energy than the heavier block. (c) Both blocks will both have the same amount of kinetic energy. (d) The heavier block will have more kinetic energy than the lighter block. (e) The magnitude of the momentum of the heavier block will be greater than the magnitude of the momentum of the lighter block. Questions 16, 17 and 18 refer to the following information: A 3.0 kg block is placed on a frictionless horizontal table. This block is connected to a 1.0 kg block with a light string as in the diagram below. A force of 160 N is then applied to the 3.0 kg block by pulling on another light string. 1 kg 3 kg 160 N Figure 2. QUESTION 16 The acceleration of the system is (a) 160 ms-2 (b) 53 ms-2 (c) 80 ms-2 (d) the same as if there was one 4 kg block instead of these two blocks (e) both (c) and (d) will be true. EGB102T1.PRACTICE cont/…  6 QUESTION 17 The tension in the light string between the two blocks is (a) zero, since the table is frictionless (b) one quarter of the tension in the other string (c) half the tension in the other string (d) none of the above QUESTION 18 The blocks are placed in exactly the same way on another horizontal table with a coefficient of kinetic friction of 0.4 and the same force is applied. The acceleration of the system would now be (a) about 60% less than for the frictionless table (b) about 40% less than for the frictionless table (c) about 10% less than for the frictionless table (d) the same as if there was one 4 kg block instead of these two blocks (e) both (c) and (d) will be true. QUESTION 19 A 3m long, 3m wide solid slider is placed on infinitely large hard surface as shown in figure 3. The space between slider and hard surface is 1mm and filled with a liquid with dynamic viscosity of 0.89 x 10-3 Pa s. Calculate the shear force acting on the slider if it is moving in a speed of 2m/s. You may neglect end effect. 1mm gap 3m long, 3m wide slider Figure 3. (a) 1.78 N (b) 16.02 N (c) 5.34 N (d) 8.01 N EGB102T1.PRACTICE cont/…  7 QUESTION 20 The differential manometer shown in figure 4 is used to measure pressure difference between pipe A and B. Pipe A is conveying water while pipe B is conveying air. If the pressure at B is 12kPa calculate the pressure at A. C 1.2m 2.3m B A Figure 4. (a) 35 kPa (b) 12 kPa (c) 23 kPa (d) 24 kPa EGB102T1.PRACTICE cont/…  8 QUESTION 21 A boat is partially submerged in water as shown in figure 5. Length and the weight of the boat are 10m and 2750kN respectively. What is the submerged depth (H) of the boat? 8m H 3m Figure 5. (a) 4.3 m (b) 6.7 m (c) 3.2 m (d) 5.0 m EGB102T1.PRACTICE cont/…  9 Questions 22 and 23 are based on figure 6 below. 0.75m A 0.85m B C 0.90m Figure 6. QUESTION 22 Figure 6 shows a side view of a triangular prism submerged in water. The prism is submerged such that its ABC triangular shape surface is placed in a vertical plane. Length of the prism (into the paper) is 1.2m. Using the details given in the figure above, calculate the horizontal pressure force applied on ABC surface. (a) 4.9 kN (b) 4.4 kN (c) 9.8 kN (d) 2.1 kN QUESTION 23 Figure shows a side view of a triangular prism submerged in water. The prism is submerged such that its ABC triangular shape surface is placed in a vertical plane. Length of the prism (into the paper) is 1.2m. Using the details given in figure 6, calculate the buoyancy force (upward) applied on the triangular prism. (a) 9.0 kN (b) 2.8 kN (c) 4.5 kN (d) 0.5 kN EGB102T1.PRACTICE cont/…  10 QUESTION 24 A 0.5m diameter circular plate is placed in a depth of 2.3m of a liquid with specific gravity 2.1. If the flat surface of the plate is placed in a horizontal plain, calculate the vertical pressure force acting on the top side of the surface. (a) 18.6 kN (b) 9.3 kN (c) 148.9 kN (d) 4.4 kN QUESTION 25 A square plate with 0.5m side length is placed in a water tank so that its centroid is in a depth of 2.9m. If the flat surface of plate is placed in vertical plan and top edge is parallel to the free surface, calculate the distance to the horizontal pressure force acting on one side of the surface from the free surface. (a) 2.907 m (b) 3.000 m (c) 2.900 m (d) 3.010 m QUESTION 26 A gate of a tank containing water and oil is kept in the closed position by applying a force F as shown in figure 7 below. Gate is designed so that it can rotate around hinge H. Width of the gate F (into the paper) is 1 m. Calculate the minimum force F required to keep the gate in closed position. 1m Water 2.5 m Hinge 1m Oil (s = 1.5) (H) Figure 7. (a) 6.31 kN (b) 14.16 kN (c) 17.17 kN (d) 5.66 kN EGB102T1.PRACTICE cont/…  11 QUESTION 27 Which of the following engineering materials have generally the lowest toughness? (a) Polyethylene. (b) Aluminium Oxide. (c) Titanium. (d) Steel. QUESTION 28 Which one of the following units is the unit of strain? (a) N/m (b) mm/mm (c) N m2 (d) MPa QUESTION 29 A cylindrical specimen of Titanium alloy of 10 mm diameter is subjected to a load of 20 kN along its axis. If the alloy has an elastic modulus of 110 GPa, how far can be extended elastically for a 1-meter length? (a) 0.381 mm (b) 2.316 mm (c) 7.60 mm (d) 11.3 mm QUESTION 30 Which one of the following statements is correct? (a) The material’s resistance to plastic deformation is the stiffness of the material. (b) Toughness is the total area under the stress-strain curve of ductile materials. (c) The strength of some metals can be significantly increased by plastic deformation. (d) Yield strength is the maximum stress a ductile material can carry before fracture. QUESTION 31 A solid bar of aluminium (E=70 GPa) has a square section of 10 mm x 10 mm and length of 500 mm. What is the final length of the bar if it is subjected to a load of 100 kN? (a) 500.715 mm. (b) 715 mm. (c) 142.85 mm. (d) 507.15 mm. EGB102T1.PRACTICE cont/…  12 QUESTION 32 The rectangular plate is deformation into the shape of parallelogram shown by the dashed line in Figure 8. Determine the average shear strain xy (in radians) at A using small strain analysis. Figure 8. Deformation of rectangular plate into the shape of parallelogram. 5 (a) 300 5 (b) 400 7 (c) 240 𝜋 7 (d) − 240 2 EGB102T1.PRACTICE cont/…  13 QUESTION 33 The lap joint in figure 9 is connected together using a 30 mm diameter bolt. The bolt is made from a material (Poisson ratio, =0.30) having a shear stress-strain diagram as shown in figure 10 (both elastic and plastic deformation). Determine the Young’s modulus of the material. Figure 9. Shear stress-strain diagram of a bolt in lap joint. (a) 70 GPa (b) 182 GPa (c) 207 GPa (d) 140 GPa QUESTION 34 A 200 mm long acrylic plastic rod of diameter 20 mm is subjected to an axial load, P (see Figure 10). If the material has Young’s Modulus, E=2.70 GPa and Poisson’s ratio, v=0.4, determine the change in diameter of the rod if the applied load is 450 N. Figure 10. Acrylic plastic rod subjected to an axial load, P. (a) 0.00424 mm (b) 0.0167 mm (c) 0.0034 mm (d) 0.0252 mm END OF PAPER EGB102T1.PRACTICE cont/…  (i) DATA AND FORMULAE SHEET CONSTANTS AND CONVERSIONS g = 9.81 m s−2 1 atm = 101,325 Pa = 101,325 N m-2 1J = 1 N m 1 N = 1 kg m s-2 1 Pa = N m-2 = kg m-1 s-2 Tc = TK - 273.15 1 cm3 = 1 x 10-6 m3 Avogadro’s number NA = 6.0231023 molecules per mole GEOMETRIC RELATIONSHIPS Circumference of a circle C=2πr Area of a circle A =  r2 Area of a sphere A = 4 r2 Volume of a cylinder V =  r2 h Volume of a sphere V = 4 r3 / 3 Second moment of area of a rectangle Ic = bd3/12 Second moment of area of a triangle Ic = bh3/36 Second moment of area of a circle Ic =  r4 /4 Second moment of area of a semicircle Ic = 0.1102 r4 TRIGONOMETRICAL RELATIONSHIPS o = opposite side to angle  a = adjacent side to angle  h = hypotenuse o sin  = h o h a cos  = h o  tan  = a a If x and y are two vectors at 90 to each other then their sum, r is such that Magnitude r2 = x2 + y2 r y Direction (with respect to x)   = tan−1 ( y / x) x EGB102T1.PRACTICE  (ii) FORMULAE Mechanics vx = u x + a xt v y = u y + a yt 1 1 x = x0 + u xt + axt 2 y = y0 + u yt + a yt 2 2 2 v x = u x + 2a x s x 2 2 v y = u y + 2a y s y 2 2 F = ma FKFr =  k N FSFr   s N F Spring = − k x mv 2 F r = ma r = R W = F s = Fs cos  W Spring = − 12 kx 2 K = 12 mv 2 U Grav = mgh U Spring = 12 kx 2 E = K +U W PAv = t P = F v = Fv cos  p = mv p F= t Where Ax 2 + Bx + C = 0 − B  B 2 − 4 AC x= 2A Fluids F=τA τ = µ (du/dy) ν=μ / 𝑝 = 𝜌𝑔𝑧 𝐹𝑅 = 𝜌𝑔(𝑦𝐶 sin 𝜃)𝐴 = 𝜌𝑔ℎ𝐶 𝐴 𝐼𝐶 𝑦𝑅 = + 𝑦𝐶 𝑦𝐶 𝐴 𝐼𝑂 = 𝐼𝐶 + 𝐴𝑦𝐶2 𝐹𝐵 = 𝜌𝑔𝑉 EGB102T1.PRACTICE  (iii) Formulae (continued) Materials 𝐹 𝜎= 𝐴 𝐿 − 𝐿𝑜 𝜀= 𝐿𝑜 𝐿 − 𝐿𝑜 𝜀= 𝐿𝑜  = L − Lo = L 𝜎 𝐸= 𝜀 𝐋 − 𝐋𝒐 %𝑬𝑳 = 𝐱 𝟏𝟎𝟎% 𝐋𝐨 𝜺𝒙 𝝂=− 𝜺𝒛 𝑑 − 𝑑𝑜 𝜀𝑥 = 𝑑𝑜 1 1 𝜎𝑦 2 𝑢𝑟 = 𝜎𝑦 𝜀𝑦 = 2 2 𝐸 V  avg = A V A=  allow 𝜋 𝛾𝑥𝑦 = − 𝜃′ 2 𝜏 𝐺= 𝛾 E = 2G (1 + ) EGB102T1.PRACTICE