The total mass of a light plane and the pilot is [...

As the temperature for a given mass of air increases, the ______.

A.dew point increases

B.dew point decreases

C.relative humidity increases

D.relative humidity decreases

Energy equals mass times the speed of light squared. This is the famous equation of Albert Einstein. It(51)to the category of the theory of relativity, and it equates energy with mass.

All things are made up of atoms. When(52)of an atom travels at almost the speed of light(53)we put more energy into it to increase the speed, it begins to in crease in mass. The energy that makes it travel fast cannot make it travel(54)the speed of light—nothing(55)light can travel that fast- so the energy goes into the thing(56)and increases its mass. Energy(57)into mass.

Why is the theory called the theory of relativity? A thing that is relative depends upon(58)else to identify it or to define it. In relativity theory we identify or define mass, time, and length(59)to the speed of light.

When something is at rest, it looks(60)in length. However, when it travels at almost the speed of light, it becomes(61). Time also changes. However, the change in time is(62)to the change in length. The length of a thing becomes short(63)time becomes long.

If you want to(64)young, relative to a friend, take a trip in a spaceship that travels at(65)the speed of light. And, although time and heartbeat seem ordinary to you in the spaceship, when you return, look at your friend; Relative to you, he or she is old.

A．prefers

B．relates

C．belongs

D．adheres

The fact that the mass of a particle is equivalent to a certain of energy means that the particle can no longer be seen as a static object, but has to be conceived as a dynamic pattern, a process involving the energy which manifest itself as the particle’s mass.

听力原文： The development of a mass culture dominated by the media has made major changes in the American political system, changes some observers feel threaten the very core of American democracy.

In the 1940s the first studies were conducted to determine whether mass media was changing American voting patterns. The studies showed that opinion leaders, not the media, were directly affecting voter behavior, although the mass media played an indirect role by influencing the opinion leaders. This discovery led to the formulation of the two-step flow theory of political communication: the mass media influence opinion leaders, who in turn influence others.

Follow-up studies in the 1960s and 1970s, however, indicated that the American political system was changing. The long-standing dominance of political parties was waning and political consultants were replacing party bosses. These consultants had advertising, public relations and opinion-polling backgrounds and had moved into the political arena to sell candidates directly to the American people through the mass media, much like others in their professions were selling soap and toothpaste.

During the twentieth century, the mass media and political advertising began playing significant roles in selling political images. Television, which has become one of the most dominant forms of mass communication in our culture, has emerged as a powerful influence in determining the political destiny of this country. It helped create a winning image for little-known Senator John Kennedy, who narrowly defeated Vice-President Richard Nixon in the 1960 presidential election; led to a decline in popularity of Lyndon B. Johnson; allowed Nixon to win the presidency eight years later by building a more positive television image; and gave national exposure to a little-known peanut farmer and former Georgia governor, Jimmy Carter. By the 1980s the presidency had been turned over to Ronald Reagan, who had made his living communicating in front of the camera. Through his effective use of television, he was soon regarded as one of the most effective communicators ever to hold the office of president.

American political candidates, managed by political consultants, are now using vote videos and direct mail as well as television advertising to get their messages across. Not everyone, however, gives TV so much credit for creating political images. Some studies have indicated that selective exposure, perception and retention play a bigger role in the election process. These studies contend, for example, that people project their own biases into television political commercials and see only what they want to see.

News reporters have been criticized for running stories about candidates' personal lives, downplaying issues and focusing too much on who is winning. Television news has also been criticized for projecting winners on election night before the polls have closed in the west. This has kept many western voters away from the polls, critics contend.

Not all campaign coverage by the media has been inadequate, however. Television has been instrumental in presenting presidential debates to the American public. Newspapers and some TV stations are now beginning to give better coverage of campaigns by analyzing political ads and reporting on their accuracy. It is hoped that such a trend will make advertisements more truthful and responsible.

(56)

Advertising is a form. of commercial mass communication designed to【C1】______the sale of a product or service, or a message on【C2】______of an institution, organization, or candidate for political office. Evidence of advertising can be found in cultures that existed thousands of years ago,【C3】______advertising only became a major industry in the 20th century. Today the【C4】______employs hundreds of thousands of people and【C5】______the behavior. and buying habits of billions of people. Advertising spending worldwide now【C6】______$350 billion per year. In the United States【C7】______about 6,000 advertising agencies help create and place advertisements in a variety of【C8】______, including newspapers, television, direct mail, radio, magazines, the Internet, and outdoor signs. Advertising is so commonplace in the United States that an average person may【C9】______from 500 to 1,000 advertisements in a single day, according to some【C10】______.

Most advertising is【C11】______to promote the sale of a particular product or service. Some advertisements,【C12】______, are intended to promote an idea or influence behavior, such as【C13】______people not to use illegal drugs or smoke cigarettes. These ads are often called public【C14】______ads. Some ads promote an institution, such as the Red Cross or the United States Army, and are known【C15】______institutional advertising. Their【C16】______is to encourage people to volunteer or donate money or services or【C17】______to improve the image of the institution doing the advertising. Advertising is also Used to promote political parties and【C18】______for political office.【C19】______advertising has become a key component of electoral【C20】______in many countries.

【C1】

A．elevate

B．advance

C．raise

D．promote

A bucket of water with total mass 23 kg is attached to a rope, which in turn is wound around a 0.050-m radius cylinder at the top of a well. A crank with a turning radius of 0.25 m is attached to the end of the cylinder and the moment of inertia of cylinder and crank is 0.12 kg?m^2. If the bucket is raised to the top of the well and released, what is the acceleration of the bucket as it falls toward the bottom of the well? _______m/s^2. (Assume rope's mass is negligible, that cylinder turns on frictionless bearings and that g = 9.8 m/s^2.)

A、3.2

B、6.3

C、7.4

D、9.8

E、98

F、12.5

G、19.8

As shown, object A and B with mass of m1 and m2 are put on a smooth surface of a table and they are connected through a light spring. Another two objects C and D are on objects A and B, and the frictional factors between A and C, B and D are not equal to zero. An external force pushes on A and B along the horizontal direction and the spring is compressed. As removing the external force during the process of A and B being apart away， for the system of A, B, C, D and the spring we have（ ）

A、Both momentum and mechanical energy are conserved;

B、Momentum is not conserved while mechanical energy is conserved;

C、Both momentum and mechanical energy are not conserved;

D、Momentum is conserved , while mechanical energy is not necessarily conserved.

Although the quality of American food may have decreased as a result of mass production and high technology, its ______ in daily life was never more visible.

A．accomplishment

B．perfection

C．prominence

D．sentiment

Since the Hawaiian Islands have never been connected to other landmasses, the great variety of plants in Hawaii must be a result of the long-distance dispersal of seeds, a process that requires both a method of transport and an equivalence between the ecology of the source area and that of the recipient area.

There is some dispute about the method of transport involved. Some biologists argue that ocean and air currents are responsible for the transport of plant seeds to Hawaii. Yet the results of flotation experiments and the low temperatures of air currents cast doubt on these hypotheses. More probable is bird transport, either externally, by accidental attachment of the seeds to feathers, or internally, by the swallowing of fruit and subsequent excretion of the seeds. While it is likely that fewer varieties of plant seeds have reached Hawaii externally than internally, more varieties are known to be adapted to external than to internal transport.

The author of the passage is primarily concerned with ______.

A．discussing different approaches biologists have taken to testing theories about the distribution of plants in Hawaii

B．discussing different theories about the transport of plant seeds to Hawaii

C．discussing the extent to which air currents are responsible for the dispersal of plant seeds to Hawaii

D．resolving a dispute about the adaptability of' plant seeds to bird transport

Although mass media are losing audiences, they still have the biggest market share of advertising.