An Airbus A320 would not turn left no matter what the pilot tried. Eventually he managed to make a high-speed emergency landing. Fortunately, no one was hurt. The cause of the near- disaster was that engineers had forgotten to reactivate four of the five spoilers on the right wing. Spoilers are the panels that help the plane to roll and hence turn. The air accident investigation blamed ‘a complex chain of human errors’, by the engineers and by the pilots who had failed to notice the problem before take-off. The A320 is a ‘fly-by-wire’ aircraft where computer- controlled electrical impulses activate the hydraulically powered spoilers and surfaces which control the movement of the plane. When the aircraft went for repair to a damaged flap, the engineers had put the spoilers into ‘maintenance mode’ to block them off from the controls so that they could be worked on independently. They had then forgotten to reactivate. According to the official report, the engineers were not guilty of ‘simple acts of neglect or ignorance. Their approach implied that they believed there were benefits to the organization if they could successfully circumvent problems to deliver the aircraft on time. With more complex aircraft it is no longer possible for maintenance staff to understand adequately the consequences of any deviation. The avoidance of future unnecessary accidents with high-technology aircraft depends on an attitude of total compliance within the industry. If a check has previously been carried out numerous times without any fault being present, it is human nature to anticipate no fault when next the check is carried out.’ (a) Why should fly-by-wire aircraft pose a more complex maintenance problem than conventional aircraft which have a physical link between the control and the flaps? (b) If you were the accident investigator, what questions would you want to ask in order to understand why this failure occurred?
> The ‘robot milkmaid’ can milk between 60 and 100 cows a day. Computer-controlled gates activated by transmitters around the cows’ necks allow the cows to enter. The machine then checks their health, connects them to the milking machine and feeds them whi
> Modern aircraft fly on automatic pilot for most of their time. Most people are blissfully unaware that when an aircraft lands in mist or fog, it is a computer that is landing it. When auto pilots can do something better than a human pilot, it makes sense
> It is a new job, as yet without a formal title, but one commentator has called it being a ‘robot wrangler’. They even proposed a possible job advert: ‘Wranglers wanted for growing fleets of robots. Your responsibilities will include evaluating robot perf
> The operations manager of a specialist company assembling seabed monitors that recorded pollution levels had a dilemma. ‘At the moment, we are producing around 40 seabed monitoring stations per year using what is basically a fixed position layout. Howeve
> A computer games developer is moving into new offices. The new office has a floor space of approximately 300 square metres in the form 20 metres by 15 metres. The company has six departments, each as identified in Figure 7.21. This also shows the approxi
> A company that produces a wide range of specialist educational kits for 5–10-year-olds is based in an industrial unit arranged in a simple layout of with six departments, each performing a separate task. The layout is shown in Figure 7.
> The assembler of customized laboratory equipment negotiates a long-term arrangement to supply a simplified standard product to be sold to forensic laboratories worldwide. This product requires an assembly sequence that takes it, in order, from Department
> My flight to Stockholm would be late landing. We were in a “stack” of planes circling above Brussels. Air traffic control had closed the runways for a short period at dawn, because of snow. Flights from all over the World were now being allocated new lan
> In an assembly operation for customized laboratory equipment the flow of materials through eight departments is shown in Table 7.2. Assuming that the direction of the flow of materials is not important, construct a relationship chart, a schematic layout
> Revisit the ‘Operations in practice’ example ‘Technology tracks customer flow in retail operations’. Then visit a supermarket and observe people’s behaviours. You may wish to try and observe which areas they move slowly past and which areas they seem to
> A gourmet burger shop has a daily demand for 250 burgers and operates for 10 hours. (a) What is the required cycle time in minutes? (b) Assuming that each burger has 7.2 minutes of work required, how many servers are required? (c) If the burger shop has
> At the theatre, the interval during a performance of ‘King Lear’ lasts for 20 minutes and in that time 86 people need to use the toilet cubicles. On average, a person spends 3 minutes in the cubicle. There are 10 cubicles available. (a) Does the theatre
> The headquarters of a major creative agency offered a service to all its global subsidiaries that included the preparation of a budget estimate that was submitted to potential clients when making a ‘pitch’ for new work
> It is a real problem for us’, said Angnyeta Larson, ‘We now have only ten working days between all the expense claims coming from the departmental coordinators and authorizing payments on the next month’s payroll. This really is not long enough and we ar
> One of the examples at the beginning of the chapter described ‘drive-through’ fast food processes. Think about (or better still, visit) a drive-through service and try mapping what you can see of the process (plus what you can infer from what may be happ
> Revisit the ‘Operations in practice’ example that examines some of the principles behind supermarket process design. Then visit a supermarket and observe peoples’ behaviour. You may wish to try and observe which areas they move slowly past and which area
> Visit a branch of a retail bank and consider the following questions: (a) What categories of service does the bank seem to offer? (b) To what extent does the bank design separate processes for each of its types of service? (c) What are the different proc
> Globalization is very much a “mixed blessing”. There is little doubt that it has lifted millions out of poverty, but it has also led to the destruction of traditional cultures in developing countries and many jobs in the developed world.’ Draw up lists o
> Here are two examples of how operations try to reduce the negative effects of having to cope with high levels of variety. Research each of them (there is plenty of information on the web) and answer the following questions. (a) What are the common featur
> How could universities adopt the practice of outsourcing more?
> The Fast and Efficient (FAC) transport Group is reviewing its fleet maintenance operations. ‘Our lease on our current maintenance and repair facilities site will expire in a year, and we need to decide how to operate in the future. Curr
> A company that produces concrete paving slabs is introducing a new range of ‘textured’ non- slip products. To do this it must invest in a new machine. Demand is forecast to be around 10,000 units per month for the first year and approximately 24,000 unit
> A data centre is ‘a facility composed of networked computers and storage that businesses or other organizations use to organize, process, store and disseminate large amounts of data. A business typically relies heavily upon the applications, services and
> Consider the music business as a supply network. How did music downloads and streaming affect each of these artists’ sales? What implications has online music transmission had for traditional music retailers?
> It sounds like a joke, but it is a genuine product innovation. It’s green, it’s square and it comes originally from Japan. It’s a square watermelon. Why square? Because Japanese grocery stores are not large and space cannot be wasted. Similarly, a round
> A janitor called Murray Spangler invented the vacuum cleaner in 1907. One year later he sold his patented idea to William Hoover whose company went on to dominate the market. Now, the Dyson vacuum cleaner has jumped from nothing to a position where it do
> According to the Ellen MacArthur Foundation, a circular economy is ‘one that is restorative and regenerative by design, and which aims to keep products, components and materials at their highest utility and value at all times, distinguishing between tech
> Innovation becomes particularly important at the interface between offerings and the people that use them. Consider two types of website: a) Those which are trying to sell something such as Amazon.com, and b) Those which are primarily concerned with givi
> We have to get this new product and fast’, said the Operations Director. ‘Our competitors are close behind us and I believe their products will be almost as good as ours when they launch them’. She was talking about a new product that the company hoped w
> Re-read the ‘Operations in practice’ example on Pret a Manger. (a) Do you think Pret a Manger fully understands the importance of its operations management? (b) What kind of operations management activities at Pret a Manger might come under the four head
> One product where customers value a very wide range of product types is that of domestic paint. Most people like to express their creativity in the choice of paints and other home decorating products that they use in their homes. Clearly, offering a wide
> During manoeuvres in the Alps, a detachment of soldiers got lost. The weather was severe and the snow was deep. In these freezing conditions, after two days of wandering, the soldiers gave up hope and became reconciled to a frozen death on the mountains.
> DSD designs, makes and supplies medical equipment to hospitals and clinics. Its success was based on their research and development culture. Although around 50 per cent of manufacturing was done in-house. Their products were relatively highly priced, but
> The Managing Partner of The Branding Partnership (TBP) was describing her business. ‘It is about four years now since we specialized in the small to medium firms’ market. Before that we also used to provide brand consultancy services for anyone who walke
> Carry out an importance–performance analysis for an amusement park. In doing this, think about the competitive factors (i.e. the key ingredients) for this offering, their level of importance and their performance using the scale. Then map these onto an i
> Giordano is one of the most widespread clothes retailers. It is based in Hong Kong and employs more than 8,000 staff in over 2,000 shops. But when it was founded, up-market shops sold high- quality products and gave good service. Cheaper clothes were pil
> ZNR Financial, a large accountancy corporation are looking to assess the operations functions in three of its locations around the world. The ZNR Malaysia operations are marginally better than the operations of many of its competitors in the region, but
> Visit the websites of two or three large oil companies such as Exxon, BP, Shell or Total. Examine how they describe their policies towards their customers, suppliers, shareholders, employees and society at large. Identify areas of the company’s operation
> Examine this simple domestic project. The project definition is to make breakfast in bed consisting of a boiled egg, toast and orange juice, using the minimum staff resources and time, and to a high quality (egg freshly boiled, warm toast, etc.). The pro
> In the oil industry, project teams are increasingly using virtual reality and visualization models of offshore structures that allow them to check out not only the original design but any modifications that have to be made during construction. (a) Why do
> Some (even relatively experienced) project managers neglect stakeholders in the project management process, preferring to ‘manage them at a distance’ rather than allow them to interfere with the project. Others argue that the benefits of stakeholder mana
> Funding comes from a variety of sources; to restore the literally irreplaceable buildings we work on. We try to reconcile historical integrity with commercial viability, and rely on the support of volunteers. So we need to involve all stakeholders all th
> The activities, their durations and precedences for designing, writing and installing a bespoke computer database are shown in Table 19.4. Draw a network diagram (Activity-on-node) for the project and calculate the fastest time in which the operation mig
> Revisit the Crossrail project example at the start of this chapter. Using, the three methods of distinguishing between projects that are described in the chapter (their volume and variety characteristics, their scale, complexity and degree of uncertainty
> Carlsberg, the brewing company, learnt of its crisis late one Friday afternoon. Something appeared to have gone wrong with the ‘widget’ in one of its cans of beer (a widget is the device in the bottom of a can which gives some canned beer its creamy char
> Every time we enter an elevator we are trusting our lives to the people who designed and made it, and, more immediately, the people who maintain it. Without effective maintenance, the elevators which are often on duty every minute of every day would lite
> An automated sandwich-making machine in a food manufacturer’s factory has six major components, with individual reliabilities as shown in Table 18.3. (a) What is the reliability of the whole system? (b) If it is decided that the wrapper
> Re-read the ‘Operations in practice’ example, ‘It’s the exception that proves the rule’. Do these examples invalidate the use of failure data in estimating component life?
> Look again at the figures in the chapter which illustrate the meaning of each performance objective for the four operations. Consider the bus company and the supermarket, and in particular consider their external customers. Draw the relative required per
> Wyco is a leading international retailer selling clothing and accessories with stores throughout the United States, Europe and the Middle East. The countries from which it sources its products include Sri Lanka, Bangladesh, India and Vietnam. It was shoc
> Although rare, air crashes do happen. Predominantly, the reason for this is human failure such as pilot fatigue. One kind of accident which is known as ‘controlled flight into terrain’, where the aircraft appears to be under control and yet still flies i
> The manager of a sweet shop decides to sample batches of sweets to check that the weight is reasonably consistent. She takes nine samples, each with 10 bags. The data below shows the average mean weight for each sample and the weight range. What control
> An animal park in Amsterdam has decided to sample 50 visitors each day (n) to see how many visitors are from overseas. The data below is for the last 7 days. If it decided to continue recording this data and plot it on a control chart for attributes, wha
> Look again at the ‘Operations in practice’ example that includes a description of the Four Seasons Canary Wharf. (a) The company has what it calls its Golden Rule; ‘Do to others (guests and staff) as you would wish others to do to you’. Why is this impor
> Tea and Sympathy’ (not a made-up name) was a British restaurant and café in the heart of New York’s West Village. It became fashionable not only with expatriate Brits but also with native New Yorkers, who were willing to queue to get in. One reason it be
> Understanding type I and type II errors is essential for surgeon’s quality planning. Appendectomy operations, for example, removal of the appendix is necessary because of the risk of it bursting, causing potentially fatal poisoning of the blood. The surg
> Re-read the ‘Operations in practice’ example ‘Ryanair reforms its view of service quality’. What does this example tell us about the trade-off between service quality and cost?
> The owner of a small wedding photography business realizes that the market is changing. “I used to take a few photos during the wedding ceremony and then formal group shots outside. It rarely took more than two hours. Around 30 photos would go in a stand
> A publishing company plans to replace its four proofreaders who look for errors in manuscripts with a new scanning machine and one proofreader in case the machine breaks down. Currently the proofreaders check 15 manuscripts every week between them. Each
> Quentin Cakes make about 20,000 cakes per year in two sizes, both based on the same recipe. Sales peak at Christmas time when demand is about 50 per cent higher than in the quieter summer period. Its customers (the stores that stock its products) order i
> While I1 is increasing, what is the direction of the magnetic force exerted on loop 2, if any? Explain.
> Refer to Example 26.2. One million muons are moving toward the ground at speed 0.9950c from an altitude of 4500 m. In the frame of reference of an observer on the ground, what are (a) the distance traveled by the muons; (b) the time of flight of the mu
> A coffee maker can be modeled as a heating element (resistance R) connected to the outlet voltage of 120 V (assumed to be dc). The heating element boils small amounts of water at a time as it brews the coffee. When bubbles of water vapor form, they carry
> 11. A projectile is launched at an angle θ above the horizontal. Ignoring air resistance, what fraction of its initial kinetic energy does the projectile have at the top of its trajectory? (a) cos θ (b) sin θ (c) ta
> Consider a closed surface that surrounds Q1 and Q2 but not Q3 or Q4. (a) Which charges contribute to the electric field at point P? (b) Would the value obtained for the net flux through the surface, calculated using only the electric field due to Q1 and
> The period of oscillation of a spring-and-mass system is 0.50 s and the amplitude is 5.0 cm. What is the magnitude of the acceleration at the point of maximum extension of the spring?
> A capacitor (capacitance = C) is connected to an ac power supply with peak voltage V and angular frequency ω. (a) During a quarter cycle when the capacitor goes from being uncharged to fully charged, what is the average current (in terms of C, V, and ω)
> Two metal spheres of radius 5.0 cm carry net charges of +1.0 µC and +0.2 µC. (a) What (approximately) is the magnitude of the electrical repulsion on either sphere when their centers are 1.00 m apart? (b) Why cannot Coulomb’s law be used to find the fo
> Make a figure analogous to Fig. 21.5 for an ideal inductor in an ac circuit. Start by assuming that the voltage across an ideal inductor is vL(t) = VL sin ωt. Make a graph showing one cycle of vL(t) and i(t) on the same axes. Then, at each of the times
> Pure water has very few ions (about 1.2 × 1014 ions per cubic centimeter), giving it a high resistivity, about 1 × 105 Ω·m at 37°C. Blood plasma has a much lower resistivity of roughly 0.6 Ω·m at 37°C due to the ions dissolved in the plasma. Assuming the
> One way to determine the location of your center of gravity is shown in the diagram. A 2.2 m long uniform plank is supported by two bathroom scales, one at either end. Initially the scales each read 100.0 N. A 1.60 m tall student then lies on top of the
> The volume of a solid cube with side s0 at temperature T0 is . Show that if Δs ≪ s0, the change in volume ΔV due to a change in temperature ΔT is given by (13-8, 13-9) and therefore that β
> Why must a camera or a projector use a converging lens? Why must the objective of a microscope or telescope be a converging lens (or a converging mirror)? Why can the eyepiece of a telescope be either converging or diverging?
> When you eat a pizza that has just come from the oven, why is it that you are apt to burn the roof of your mouth with the first bite although the crust of the pizza feels only warm to your hand?
> Rank the final speeds of the three rocks.
> 4A strip of copper 2.0 cm wide carries a current I = 30.0 A to the right. The strip is in a magnetic field B = 5.0 T into the page. (a) What is the direction of the average magnetic force on the conduction electrons? (b) The Hall voltage is 20.0 μV. Wha
> (a) Find the value of a single capacitor to replace the three capacitors in the diagram. (b) What is the potential difference across the 12 µF capacitor at the left side of the diagram? (c) What is the charge on the 12 µF capa
> Find the magnetic field at point P, the midpoint of the top side of the square.
> An external magnetic field parallel to the central axis of a 50 turn coil of radius 5.0 cm increases from 0 to 1.8 T in 3.6 s. (a) If the resistance of the coil is 2.8 Ω, what is the magnitude of the induced current in the coil? (b) What is the directi
> A sound wave with an intensity level of 80.0 dB is incident on an eardrum of area 0.600 × 10−4 m2. How much energy is incident on the eardrum in 3.00 min?
> Describe the difference between specular and diffuse reflection. Give some examples of each.
> The mechanical power output of a cyclist moving at a constant speed of 6.0 m/s on a level road is 120 W. (a) What is the force exerted on the cyclist and the bicycle by the air? (b) By bending low over the handlebars, the cyclist reduces the air resist
> When the NASA Rover Spirit successfully landed on Mars in January of 2004, Mars was 170.2 × 106 km from Earth. Twenty-one days later, when the Rover Opportunity landed on Mars, Mars was 198.7 × 106 km from Earth. (a) How long did it take for a one-way t
> The period of oscillation of a simple pendulum does not depend on the mass of the bob. By contrast, the period of a mass-spring system does depend on mass. Explain the apparent contradiction. [Hint: What provides the restoring force in each case? How doe
> Is the buoyant force on a soap bubble greater than the weight of the bubble? If not, why do soap bubbles sometimes appear to float in air?
> Show that each of these statements implies that v ≪ c, which means that v can be considered a nonrelativistic speed: (a) γ − 1 ≪ 1 [Eq. (26-26)]; (b) K ≪ mc2 [Eq. (26-27)]; (c) p ≪ mc [Eq. (26-28)]; (d) K ≈ p2/(2m).
> An automobile with a mass of 1600 kg has a speed of 30.0 m/s. What is its kinetic energy?
> 1. The compound microscope is made from two lenses. Which statement is true concerning the operation of the compound microscope? (a) Both lenses form real images. (b) Both lenses form virtual images. (c) The lens closest to the object forms a virtual ima
> 1. A baryon can be composed of (a) any odd number of quarks. (b) three quarks with three different colors. (c) three quarks of matching color. (d) a colorless quark-antiquark pair. 2. Mesons are composed of (a) any odd number of quarks. (b) three quarks
> In Problem 13, what is the kinetic energy of the muon? [Hint: The muon is nonrelativistic, so its kinetic energy-momentum relationship is K = p2/(2m). The antineutrino is extremely relativistic.]
> Give an example of an object whose acceleration is (a) in the same direction as its velocity, (b) opposite its velocity, and (c) perpendicular to its velocity.
> 1. Solid lead has more than four times the mass density of solid aluminum. What is the main reason that lead is so much more dense? (a) The Pb atom is smaller than the Al atom. (b) The Pb nucleus is smaller than the Al nucleus. (c) The Pb nucleus is more
> An ac circuit contains a 12.5 Ω resistor, a 5.00 µF capacitor, and a 3.60 mH inductor connected in series to an ac generator with an output voltage of 50.0 V (peak) and frequency of 1.59 kHz. Find the impedance, the power factor, and the phase difference
> Suppose a satellite is in a circular orbit 3.0 Earth radii above the surface of Earth (4.0 Earth radii from the center of Earth). By how much does it have to increase its speed in order to be able to escape Earth? [Hint: You need to calculate the orbital
> A harpsichord string is made of yellow brass (Young's modulus 90 GPa, tensile strength 0.63 GPa, mass density 8500 kg/m3). When tuned correctly, the tension in the string is 59.4 N, which is 93% of the maximum tension that the string can endure without b
> When batteries are connected in parallel, they should have the same emf. However, batteries connected in series need not have the same emf. Explain.
> Four objects move to the right with constant acceleration. Rank the motion diagrams in order of the magnitude of the acceleration, from greatest to least. The time interval between dots is the same in each diagram.
> Some claim that mountain climbers suffer from headaches due not only to a lack of oxygen in the brain, but also to the expansion of the brain in the cranium. Find the fractional change of the brain’s volume due to a reduction in pressure from 101 kPa at
> In the study of thermodynamics, we thought of a refrigerator as a reversed heat engine. (a) Explain how a generator is a reversed electric motor. (b) What kind of device is a reversed loudspeaker?
> One of the tricky things about learning to sail is distinguishing the “true wind” from the “apparent wind.” The true wind is the velocity of the air relative to the water, whereas th
