科技英语课后题答案

答案：练习1：1. A rocket is made of metal.2. A battery is a device that gives a constant voltage.3. What a good computer (it is)！How good a computer (it is)!4. In a computer, the tendency is to operate as high a clock rate as possible.5. A body must be made to move, or no work will be done.6. This railroad is 6 times longer than that one.7. Ordinary windows cannot withstand so large a force.8. This value is one third what it was.9. This is too complicated a problem for us to go into here.10. It will take a computer half an hour to solve this problem.练习2：1. We obtained this result with great ease.2. There are many instruments in common use.3. Forces are measured in newtons.4. The concept of gravity will be introduced in the next section.5. Of the first three chapters, the first one introduces nuclear energy.6. These two values differ by 5.7. This new device has many advantages over those old ones.8. We need to solve these equations for those unknowns.9. In everyday life, forces seem to be transmitted only by “direct contact”.10. This result looks correct.11 . This point cannot be overemphasized.12. Their distance apart is very small.练习3：1. This quantity of information is approximately proportional to the range of frequencies usable/ available.2. All the chemistry textbooks available mention this phenomenon.3.In a normal atom, the number of protons is equal to the number of electrons present.4.In this paper there is nothing special.5. In this case the signal waveform can be transmitted undistorted.6. The rays of the sun reach the earth almost parallel.7. This is a positive number larger than 1.8. Such sequences must have a limit either finite or infinite.9. This method can be used to handle problems too complex to be solved by inspection.10. All systems, living and mechanical, are (both) information and feedback control systems.11. Simple in structure and low in price, this machine is warmly received by users.12. Contrary to common belief, Dr.Gordon was not the first to use the metal.13. The ball is moving parallel to the table’s surface.14. This circuit operates similar to a counter.15. This is a straight ling 5 meters long.练习4：1.One of the advantages of these new devices over the old ones is their small size.2.Because of its great importance, this circuit will be discussed in detail later.4.Our discussion of this topic will be presented in the next chapter.6. The density of water is higher than that of ice.7. By efficiency one means the ratio of output to input.9. These results are in agreement with the experimental ones.10. These computers are similar to those in our labortory.练习51. This is any constant not zero.6. These devices have been factory calibrated accurately.11. These measurements must be made at many frequencies, a rather time-consuming and tedious task.13. This method has an advantage over that of example 2.17. The variation of speed with time is shown in Fig. 6-6.练习73. The stationary electric charge can never interact with a magnet.4. Eq. (5-18) cannot be satisfied for all values of x and t.5. None of the textbooks available have mentioned this problem.7. This instrument does not appear to be good as that one.9. This figure indicates that the speed of light is not infinite as many people believed at that time.10. These rules are not valid for all types of circuits.练习8：2. The better one knows C, the harder it seems to be to avoid writing C ++ in C style3. In a well-designed instrument, R4 may be as high as 105. In this case, switch resistance is much less important.8. The whale’s body is a thousand times heavier than its brain, while the elephant’s body is about 5 hundred times as heavy.9. There are probably as many different techniques as there are service men.练习9：1. In recent years, they have been designing a new kind of product.2. We discussed this problem briefly in chapter 1.3. That aircraft is being assembled.4. It has been/ is more than 10years since this professor became an academician.5. By the end of this year, these engineers will have worked in this research institute for 20years.6. The world is always changing.7. Up to now, we have been concerned only with the motion of particles.8. This is the first time they have ever developed this new kind of computer.9. A few years ago, the NASA said that they would establish a space factory.10. That chief physician told us that his research group had found a new kind of virus.练习10：1. Full use should be made of the computers available.or: The computer available should be made full use of.2. Each point is assigned a number.3. Now we are told that I is proportional to V.4. Nonlinear equations will be discussed in chapter5.5. This stone is being acted on by 3 forces.6. The reader may not be convinced that this is true.练习11：2. To deform anything requires a force.3. To do work is to move a body through a distance.5. In this laboratory there are many devices for students to choose from.7. This case is particularly simple to analyze.8. It requires much time and effort for scientific knowledge to be applied to the practical affairs of life.9. There are wide differences in the ability of various substances to conduct heat.10. Gravity is the tendency of all objects to attract each other.11. This unit determines which of these operations to perform.12. In some experiments, you will be told what to measure and what instruments to use.练习12：对比练习11第一题：All matter is found to be composed of atoms or molecules.Ⅲ1. This is a device consisting f five parts.2. Resistance equals voltage divided by current.3. Flowing through a circuit, the current will meet some opposition.4. Expressed in a formula, this law can be written as follows.5. This battery, properly used, may last for a long time.6. A force can be resolved into two components, one of them (being) vertical and the other horizontal.Ⅳ1. Let us construct, with the origin as center, a circle of radius R.2. A tiny nucleus is at the center of the atom, with its electrons some distance away.3. With no friction present, energy would not be lost.4. This device was designed with security in mind.5. The equations with V proportional to F can be solved this way.6. A keyboard is the device with buttons on it.练习13：1. There are many ways of generating electricity.4. Upon/ On rearranging the above equations, we obtain the following set of equations.5. In using the above equation, attention must be paid to the sign.6. Compressing a gas quickly raises its temperature.8. The more crowded the conditions, the greater the chances of epidemics breaking out.练习17：1. It is necessary to know what units are used for measuring the quantity of heat.2. This book tells the reader what electric circuits are and what we do with them.4. Force is what makes bodies move.5. What this chapter describes is extremely important.7. This concept will be introduced in what the author hopes is a clear and concise manner.9. What we call the weight of a body is really the attractive force which the earth exerts on the body.10. The current in this branch has become 10 times what it was.练习182. There is almost no natural science but requires mathematics.4. It is unfortunate that early cancer is painless; otherwise, cancer would not be the problem (that) it is.9. Faraday was the scientist who discovered electromagnetic induction.10. Gain is the number of times an amplifier amplifies a signal.练习19：1. These two laws are the foundation on which all other laws in electricity are built.6. They derived an equation, the solution to which is very simple.8. The author would like to thank the editors of the series of which this book is a part.练习20：1. We can let the x-axis coincide with one of the forces, which will simplify the problem.5. As the name shows, a conductor is the substance that conducts electric current.6. This resulted in the creation of “high-speed mechanics”, or as it is called relativistic mechanics.7. The result is as shown in Fig. 2.练习22：1. There does exist water on that planet.2. It is not clear by what method it is that this equation can be solved.4. It is this advantage of the device with which we are concerned.5. It may well be this flaw that often leads to the failure of that computer.6. It is what this paper describes that has attracted many readers.练习23：3. Below / Here is a table of conductivities of some metals we are familiar with.6. Shown in Fig. 1-1 is a block diagram of a digital computer.7. By speed is meant the ratio of distance to time.9. This problem we shall discuss in detail later.10. By no means do ions move in a wire.练习24：3. It is necessary to find the current through and the voltage across the capacitor.5. This value is less than or equal to unity.6. No matter how high the density, solar matter can be considered as an ideal gas.7.Different emf’s result in potential gradients. hence electric fields.。