The dimensions for the flexural rigidity of a beam element in mass (M), length (L) and time (T) is given by ?->(Show Answer!)

1. The dimensions for the flexural rigidity of a beam element in mass (M), length (L) and time (T) is given by

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MCQ->The dimensions for the flexural rigidity of a beam element in mass (M), length (L) and time (T) is given by....

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 horizontal fixed beam is fixed at both it ends A and B. During loading, the right support sinks by an amount δ. Flexural rigidity of the beam is uniform and is equal to EI. Length of the beam is L. What is the moment developed at the centre of the beam due to sinking of the support ?....

MCQ-> Read passage carefully. Answer the questions by selecting the most appropriate option (with reference to the passage). PASSAGE 1We use the word culture quite casually when referring to a variety of thoughts and actions. I would like to begin my attempt to define cultures by a focus on three of its dictionary meanings that I think are significant to our understanding of the general term-culture. We often forget that it's more essential usage is as a verb rather than as a noun, since the noun follows froth the activities involved in the verb. Thus the verb, to culture, means to cultivate. This can include at least three activities: to artificially grow microscopic organisms; to improve and refine the customs, manners and activities of one's life; to give attention to the mind as part of what goes into the making of what we call civilization, or what was thought to be the highest culture. In short, one might argue that culture is the intervention of human effort in refining and redefining that which is natural, but that it gradually takes on other dimensions in the life of the individual, and even more in the interface between the individual and society. When speaking of society, this word also requires defining. Society, it has been said, is what emerges from a network of interactions between people that follow certain agreed upon and perceptible patterns. These arc determined by ideas of status, hierarchy and a sense of community governing the network. They are often, but not invariably, given a direction by those who control the essentials in how a society functions, as for instance, its economic resources, its technology and its value systems. The explanation and justification for who controls these aspects of a society introduces the question of its ideology and often its form. The resulting patterns that can be differentiated from segment to segment of the society are frequently called its cultures. Most early societies register inequalities, The access of their members to wealth and status varies. The idea of equality therefore has many dimensions. All men and women may be said to be equal in the eyes of god, but may at the same time be extremely differentiated in terms of income and social standing, and therefore differentiated in the eyes of men and women. This would not apply to the entire society. There may be times when societies conform to a greater degree of equality, but such times may be temporary. It has been argued that on a pilgrimage, the status of every pilgrim is relatively similar but at the end returns to inequalities. Societies are not static and change their forms and their rules of functioning. Cultures are reflections of these social patterns, so they also change. My attempt in this introduction is to explain how the meaning of a concept such as culture has changed in recent times and has come to include many more facets than it did earlier. What we understand as the markers of culture have gone way beyond what we took them to be a century or two ago. Apart from items of culture, which is the way in which culture as heritage was popularly viewed, there is also the question of the institutions and social codes that determine the pattern of living, and upon which pattern a culture is constructed. Finally, there is the process of socialization into society and culture through education. There is a historical dimension to each of these as culture and history are deeply intertwined. There is also an implicit dialogue between the present and the past reflected in the way in which the readings of the past changed over historical periods. Every. society has its cultures, namely, the patterns of how the people of that society live. In varying degrees this would refer to broad categories that shape life, such as the environment that determines the relationship with the natural world, technology that enables a control over the natural world, political-economy that organizes the larger vision of a society as a community or even as a state, structures of social relations that ensure its networks of functioning, religion that appeals to aspirations and belief, mythology that may get transmuted into literature and philosophy that teases the mind and the imagination with questions. The process of growth is never static therefore there are mutations and changes within the society. There is communication and interaction with other societies through which cultures evolve and mutate. There is also the emergence of subcultures that sometimes take the form of independent and dominant cultures or amoeba-like breakaway to form new cultures. Although cultures coincide with history and historical change, the consciousness of a category such as culture, in the emphatic sense in which the term is popularly used these days, emerges in the eighteenth century in Europe. The ideal was the culture of elite groups, therefore sometimes a distinction is made between what carne to be called 'high culture' that of the elite, and low culture' that of those regarded as not being of the elite, and sometimes described as 'popular'. Historical records of elite cultures in forms such as texts and monuments for instance, received larger patronage and symbolized the patterns of life of dominant groups. They were and are more readily available as heritage than the objects of the socially lower groups in society whose less durable cultural manifestations often do not survive. This also predisposed people to associate culture as essentially that of the elite.What is the central idea of the passage?
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MCQ-> Analyse the following passage and provide appropriate answers for the questions that follow: Each piece, or part, of the whole of nature is always merely an approximation to the complete truth, or the complete truth so far as we know it. In fact, everything we know is only some kind of approximation, because we know that we do not know all the laws as yet. Therefore, things must be learned only to be unlearned again or, more likely, to be corrected. The principal of science, the definition, almost, is the following: The test of all knowledge is experiment. Experiment is the sole judge of scientific “truth.” But what is the source of knowledge? Where do the laws that are to be tested come from? Experiment, itself, helps to produce these laws, in the sense that it gives us hints. But also needed is imagination to create from these laws, in the sense that it gives us hints. But also needed is imagination to create from these hints the great generalizations – to guess at the wonderful, simple, but very strange patterns beneath them all, and then to experiment to check again whether we have made the right guess. This imagining process is so difficult that there is a division of labour in physics: there are theoretical physicists who imagine, deduce, and guess at new laws, but do not experiment; and then there are experimental physicists who experiment, imagine, deduce, and guess. We said that the laws of nature are approximate: that we first find the “wrong” ones, and then we find the “right” ones. Now, how can an experiment be “wrong”? First, in a trivial way: the apparatus can be faulty and you did not notice. But these things are easily fixed and checked back and forth. So without snatching at such minor things, how can the results of an experiment be wrong? Only by being inaccurate. For example, the mass of an object never seems to change; a spinning top has the same weight as a still one. So a “law” was invented: mass is constant, independent of speed. That “law” is now found to be incorrect. Mass is found is to increase with velocity, but appreciable increase requires velocities near that of light. A true law is: if an object moves with a speed of less than one hundred miles a second the mass is constant to within one part in a million. In some such approximate form this is a correct law. So in practice one might think that the new law makes no significant difference. Well, yes and no. For ordinary speeds we can certainly forget it and use the simple constant mass law as a good approximation. But for high speeds we are wrong, and the higher the speed, the wrong we are. Finally, and most interesting, philosophically we are completely wrong with the approximate law. Our entire picture of the world has to be altered even though the mass changes only by a little bit. This is a very peculiar thing about the philosophy, or the ideas, behind the laws. Even a very small effect sometimes requires profound changes to our ideas.Which of the following options is DEFINITLY NOT an approximation to the complete truth?
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