It is easier to roll a stone up a sloping road than to lift it vertical upwards because ?->(Show Answer!)

1. It is easier to roll a stone up a sloping road than to lift it vertical upwards because

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MCQ->It is easier to roll a stone up a sloping road than to lift it vertical upwards because....

MCQ->In a school, students were called for the Flag Hoisting ceremony on August 15. After the ceremony, small boxes of sweets were distributed among the students. In each class, the student with roll no. 1 got one box of sweets, student with roll number 2 got 2 boxes of sweets, student with roll no. 3 got 3 boxes of sweets and so on. In class III, a total of 1200 boxes of sweets were distributed. By mistake one of the students of class III got double the sweets he was entitled to get. Identify the roll number of the student who got twice as many boxes of sweets as compared to his entitlement.....

MCQ-> Before the internet, one of the most rapid changes to the global economy and trade was wrought by something so blatantly useful that it is hard to imagine a struggle to get it adopted: the shipping container. In the early 1960s, before the standard container became ubiquitous, freight costs were I0 per cent of the value of US imports, about the same barrier to trade as the average official government import tariff. Yet in a journey that went halfway round the world, half of those costs could be incurred in two ten-mile movements through the ports at either end. The predominant ‘break-bulk’ method, where each shipment was individually split up into loads that could be handled by a team of dockers, was vastly complex and labour-intensive. Ships could take weeks or months to load, as a huge variety of cargoes of different weights, shapes and sizes had to be stacked together by hand. Indeed, one of the most unreliable aspects of such a labour-intensive process was the labour. Ports, like mines, were frequently seething pits of industrial unrest. Irregular work on one side combined with what was often a tight-knit, well - organized labour community on the other.In 1956, loading break-bulk cargo cost $5.83 per ton. The entrepreneurial genius who saw the possibilities for standardized container shipping, Malcolm McLean, floated his first containerized ship in that year and claimed to be able to shift cargo for 15.8 cents a ton. Boxes of the same size that could be loaded by crane and neatly stacked were much faster to load. Moreover, carrying cargo in a standard container would allow it to be shifted between truck, train and ship without having to be repacked each time.But between McLean’s container and the standardization of the global market were an array of formidable obstacles. They began at home in the US with the official Interstate Commerce Commission, which could prevent price competition by setting rates for freight haulage by route and commodity, and the powerful International Longshoremen's Association (ILA) labour union. More broadly, the biggest hurdle was achieving what economists call ‘network effects’: the benefit of a standard technology rises exponentially as more people use it. To dominate world trade, containers had to be easily interchangeable between different shipping lines, ports, trucks and railcars. And to maximize efficiency, they all needed to be the same size. The adoption of a network technology often involves overcoming the resistance of those who are heavily invested in the old system. And while the efficiency gains are clear to see, there are very obvious losers as well as winners. For containerization, perhaps the most spectacular example was the demise of New York City as a port.In the early I950s, New York handled a third of US seaborne trade in manufactured goods. But it was woefully inefficient, even with existing break-bulk technology: 283 piers, 98 of which were able to handle ocean-going ships, jutted out into the river from Brooklyn and Manhattan. Trucks bound‘ for the docks had to fiive through the crowded, narrow streets of Manhattan, wait for an hour or two before even entering a pier, and then undergo a laborious two-stage process in which the goods foot were fithr unloaded into a transit shed and then loaded onto a ship. ‘Public loader’ work gangs held exclusive rights to load and unload on a particular pier, a power in effect granted by the ILA, which enforced its monopoly with sabotage and violence against than competitors. The ILA fought ferociously against containerization, correctly foreseeing that it would destroy their privileged position as bandits controlling the mountain pass. On this occasion, bypassing them simply involved going across the river. A container port was built in New Jersey, where a 1500-foot wharf allowed ships to dock parallel to shore and containers to be lified on and off by crane. Between 1963 - 4 and 1975 - 6, the number of days worked by longshoremen in Manhattan went from 1.4 million to 127,041.Containers rapidly captured the transatlantic market, and then the growing trade with Asia. The effect of containerization is hard to see immediately in freight rates, since the oil price hikes of the 1970s kept them high, but the speed with which shippers adopted; containerization made it clear it brought big benefits of efficiency and cost. The extraordinary growth of the Asian tiger economies of Singapore, Taiwan, Korea and Hong Kong, which based their development strategy on exports, was greatly helped by the container trade that quickly built up between the US and east Asia. Ocean-borne exports from South Korea were 2.9 million tons in 1969 and 6 million in 1973, and its exports to the US tripled.But the new technology did not get adopted all on its own. It needed a couple of pushes from government - both, as it happens, largely to do with the military. As far as the ships were concerned, the same link between the merchant and military navy that had inspired the Navigation Acts in seventeenth-century England endured into twentieth-century America. The government's first helping hand was to give a spur to the system by adopting it to transport military cargo. The US armed forces, seeing the efficiency of the system, started contracting McLean’s company Pan-Atlantic, later renamed Sea-land, to carry equipment to the quarter of a million American soldiers stationed in Western Europe. One of the few benefits of America's misadventure in Vietnam was a rapid expansion of containerization. Because war involves massive movements of men and material, it is often armies that pioneer new techniques in supply chains.The government’s other role was in banging heads together sufficiently to get all companies to accept the same size container. Standard sizes were essential to deliver the economies of scale that came from interchangeability - which, as far as the military was concerned, was vital if the ships had to be commandeered in case war broke out. This was a significant problem to overcome, not least because all the companies that had started using the container had settled on different sizes. Pan- Atlantic used 35- foot containers, because that was the maximum size allowed on the highways in its home base in New Jersey. Another of the big shipping companies, Matson Navigation, used a 24-foot container since its biggest trade was in canned pineapple from Hawaii, and a container bigger than that would have been too heavy for a crane to lift. Grace Line, which largely traded with Latin America, used a foot container that was easier to truck around winding mountain roads.Establishing a US standard and then getting it adopted internationally took more than a decade. Indeed, not only did the US Maritime Administration have to mediate in these rivalries but also to fight its own turf battles with the American Standards Association, an agency set up by the private sector. The matter was settled by using the power of federal money: the Federal Maritime Board (FMB), which handed out to public subsidies for shipbuilding, decreed that only the 8 x 8-foot containers in the lengths of l0, 20, 30 or 40 feet would be eligible for handouts.Identify the correct statement:
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MCQ-> In a modern computer, electronic and magnetic storage technologies play complementary roles. Electronic memory chips are fast but volatile (their contents are lost when the computer is unplugged). Magnetic tapes and hard disks are slower, but have the advantage that they are non-volatile, so that they can be used to store software and documents even when the power is off.In laboratories around the world, however, researchers are hoping to achieve the best of both worlds. They are trying to build magnetic memory chips that could be used in place of today’s electronics. These magnetic memories would be nonvolatile; but they would also he faster, would consume less power, and would be able to stand up to hazardous environments more easily. Such chips would have obvious applications in storage cards for digital cameras and music- players; they would enable handheld and laptop computers to boot up more quickly and to operate for longer; they would allow desktop computers to run faster; they would doubtless have military and space-faring advantages too. But although the theory behind them looks solid, there are tricky practical problems and need to be overcome.Two different approaches, based on different magnetic phenomena, are being pursued. The first, being investigated by Gary Prinz and his colleagues at the Naval Research Laboratory (NRL) in Washington, D.c), exploits the fact that the electrical resistance of some materials changes in the presence of magnetic field— a phenomenon known as magneto- resistance. For some multi-layered materials this effect is particularly powerful and is, accordingly, called “giant” magneto-resistance (GMR). Since 1997, the exploitation of GMR has made cheap multi-gigabyte hard disks commonplace. The magnetic orientations of the magnetised spots on the surface of a spinning disk are detected by measuring the changes they induce in the resistance of a tiny sensor. This technique is so sensitive that it means the spots can be made smaller and packed closer together than was previously possible, thus increasing the capacity and reducing the size and cost of a disk drive. Dr. Prinz and his colleagues are now exploiting the same phenomenon on the surface of memory chips, rather spinning disks. In a conventional memory chip, each binary digit (bit) of data is represented using a capacitor-reservoir of electrical charge that is either empty or fill -to represent a zero or a one. In the NRL’s magnetic design, by contrast, each bit is stored in a magnetic element in the form of a vertical pillar of magnetisable material. A matrix of wires passing above and below the elements allows each to be magnetised, either clockwise or anti-clockwise, to represent zero or one. Another set of wires allows current to pass through any particular element. By measuring an element’s resistance you can determine its magnetic orientation, and hence whether it is storing a zero or a one. Since the elements retain their magnetic orientation even when the power is off, the result is non-volatile memory. Unlike the elements of an electronic memory, a magnetic memory’s elements are not easily disrupted by radiation. And compared with electronic memories, whose capacitors need constant topping up, magnetic memories are simpler and consume less power. The NRL researchers plan to commercialise their device through a company called Non-V olatile Electronics, which recently began work on the necessary processing and fabrication techniques. But it will be some years before the first chips roll off the production line.Most attention in the field in focused on an alternative approach based on magnetic tunnel-junctions (MTJs), which are being investigated by researchers at chipmakers such as IBM, Motorola, Siemens and Hewlett-Packard. IBM’s research team, led by Stuart Parkin, has already created a 500-element working prototype that operates at 20 times the speed of conventional memory chips and consumes 1% of the power. Each element consists of a sandwich of two layers of magnetisable material separated by a barrier of aluminium oxide just four or five atoms thick. The polarisation of lower magnetisable layer is fixed in one direction, but that of the upper layer can be set (again, by passing a current through a matrix of control wires) either to the left or to the right, to store a zero or a one. The polarisations of the two layers are then either the same or opposite directions.Although the aluminum-oxide barrier is an electrical insulator, it is so thin that electrons are able to jump across it via a quantum-mechanical effect called tunnelling. It turns out that such tunnelling is easier when the two magnetic layers are polarised in the same direction than when they are polarised in opposite directions. So, by measuring the current that flows through the sandwich, it is possible to determine the alignment of the topmost layer, and hence whether it is storing a zero or a one.To build a full-scale memory chip based on MTJs is, however, no easy matter. According to Paulo Freitas, an expert on chip manufacturing at the Technical University of Lisbon, magnetic memory elements will have to become far smaller and more reliable than current prototypes if they are to compete with electronic memory. At the same time, they will have to be sensitive enough to respond when the appropriate wires in the control matrix are switched on, but not so sensitive that they respond when a neighbouring elements is changed. Despite these difficulties, the general consensus is that MTJs are the more promising ideas. Dr. Parkin says his group evaluated the GMR approach and decided not to pursue it, despite the fact that IBM pioneered GMR in hard disks. Dr. Prinz, however, contends that his plan will eventually offer higher storage densities and lower production costs.Not content with shaking up the multi-billion-dollar market for computer memory, some researchers have even more ambitious plans for magnetic computing. In a paper published last month in Science, Russell Cowburn and Mark Well and of Cambridge University outlined research that could form the basis of a magnetic microprocessor — a chip capable of manipulating (rather than merely storing) information magnetically. In place of conducting wires, a magnetic processor would have rows of magnetic dots, each of which could be polarised in one of two directions. Individual bits of information would travel down the rows as magnetic pulses, changing the orientation of the dots as they went. Dr. Cowbum and Dr. Welland have demonstrated how a logic gate (the basic element of a microprocessor) could work in such a scheme. In their experiment, they fed a signal in at one end of the chain of dots and used a second signal to control whether it propagated along the chain.It is, admittedly, a long way from a single logic gate to a full microprocessor, but this was true also when the transistor was first invented. Dr. Cowburn, who is now searching for backers to help commercialise the technology, says he believes it will be at least ten years before the first magnetic microprocessor is constructed. But other researchers in the field agree that such a chip, is the next logical step. Dr. Prinz says that once magnetic memory is sorted out “the target is to go after the logic circuits.” Whether all-magnetic computers will ever be able to compete with other contenders that are jostling to knock electronics off its perch — such as optical, biological and quantum computing — remains to be seen. Dr. Cowburn suggests that the future lies with hybrid machines that use different technologies. But computing with magnetism evidently has an attraction all its own.In developing magnetic memory chips to replace the electronic ones, two alternative research paths are being pursued. These are approaches based on:
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MCQ-> A difficult readjustment in the scientist's conception of duty is imperatively necessary. As Lord Adrain said in his address to the British Association, unless we are ready to give up some of our old loyalties, we may be forced into a fight which might end the human race. This matter of loyalty is the crux. Hitherto, in the East and in the West alike, most scientists, like most other people, have felt that loyalty to their own state is paramount. They have no longer a right to feel this. Loyalty to the human race must take its place. Everyone in the West will at once admit this as regards Soviet scientists. We are shocked that Kapitza who was Rutherford's favourite pupil, was willing when the Soviet government refused him permission to return to Cambridge, to place his scientific skill at the disposal of those who wished to spread communism by means of H-bombs. We do not so readily apprehend a similar failure of duty on our own side. I do not wish to be thought to suggest treachery, since that is only a transference of loyalty to another national state. I am suggesting a very different thing; that scientists the world over should join in enlightening mankind as to the perils of a great war and in devising methods for its prevention. I urge with all the emphasis at my disposal that this is the duty of scientists in East and West alike. It is a difficult duty, and one likely to entail penalties for those who perform it. But, after all, it is the labours of scientists which have caused the danger and on this account, if on no other, scientists must do everything in their power to save mankind from the madness which they have made possible. Science from the dawn of History, and probably longer, has been intimately associated with war. I imagine that when our ancestors descended from the trees they were victorious over the arboreal conservatives because flints were sharper than coconuts. To come to more recent times, Archimedes was respected for his scientific defense of Syracuse against the Romans; Leonardo obtained employment under the Duke of Milan because of his skill in fortification, though he did mention in a postscript that he could also paint a bit. Galileo similarly derived an income from the Grant Duke of Tuscany because of his skill in calculating the trajectories of projectiles. In the French Revolution, those scientists who were not guillotined devoted themselves to making new explosives. There is therefore no departure from tradition in the present day scientists manufacture of A-bombs and H-bomb. All that is new is the extent of their destructive skill.I do not think that men of science can cease to regard the disinterested pursuit of knowledge as their primary duty. It is true that new knowledge and new skills are sometimes harmful in their effects, but scientists cannot profitably take account of this fact since the effects are impossible to foresee. We cannot blame Columbus because the discovery of the Western Hemisphere spread throughout the Eastern Hemisphere an appallingly devastating plague. Nor can we blame James Watt for the Dust Bowl although if there had been no steam engines and no railways the West would not have been so carelessly or so quickly cultivated To see that knowledge is wisely used in primarily the duty of statesmen, not of science; but it is part of the duty of men of science to see that important knowledge is widely disseminated and is not falsified in the interests of this or that propaganda.Scientific knowledge has its dangers; but so has every great thing. And over and beyond the dangers with which it threatens the present, it opens up, as nothing else can, the vision of a possible happy world, a world without poverty, without war, with little illness. And what is perhaps more than all, when science has mastered the forces which mould human character, it will be able to produce populations in which few suffer from destructive fierceness and in which the great majority regard other people, not as competitors, to be feared, but as helpers in a common task. Science has only recently begun to apply itself to human beings except in their purely physical aspect. Such science as exists in psychology and anthropology has hardly begun to affect political behaviour or private ethics. The minds of men remain attuned to a world that is fast disappearing. The changes in our physical environment require, if they are to bring well being, correlative changes in our beliefs and habits. If we cannot effect these changes, we shall suffer the fate of the dinosaurs, who could not live on dry land.I think it is the duty of science. I do not say of every individual man of science, to study the means by which we can adapt ourselves to the new world. There are certain things that the world quite obviously needs; tentativeness, as opposed to dogmatism in our beliefs: an expectation of co-operation, rather than competition, in social relations, a lessening of envy and collective hatred These are things which education could produce without much difficulty. They are not things adequately sought in the education of the present day.It is progress in the human sciences that we must look to undo the evils which have resulted from a knowledge of the physical world hastily and superficially acquired by populations unconscious of the changes in themselves that the new knowledge has made imperative. The road to a happier world than any known in the past lies open before us if atavistic destructive passion can be kept in leash while the necessary adaptations are made. Fears are inevitable in our time, but hopes are equally rational and far more likely to bear good fruit. We must learn to think rather less of the dangers to be avoided than of the good that will be within our grasp if we believe in it and let it dominate our thoughts. Science, whatever unpleasant consequences it may have by the way, is in its very nature a liberator, a liberator of bondage to physical nature and, in time to come a liberator from the weight of destructive passion. We are on the threshold of utter disaster or unprecedented glorious achievement. No previous age has been fraught with problems so momentous and it is to science that we must look for happy issue.The duty of science, according to the author is :-
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