What is the impact of automobiles on transportation?

More cars do bring a lot of traffic problems, the advantage of the car is that people are fast, convenient and comfortable travel tools, but also the ideal that Chinese generations have dreamed of, today it has finally been realized, but it has also added more troubles to people. Short-distance travel becomes slower, there is nowhere to stop at the destination, long traffic jams and queues, and a lot of car exhaust fumes are breathing, which makes people upset.

Traffic congestion, now many cities in China, public security traffic police expressly, ban electric vehicles on the road, in order to protect people's lives and safety as an excuse, the essence is that once the number of cars is reduced, it will inevitably affect the income of fines.

Traffic congestion, with the expansion of Guangzhou's urban scale and urban spatial layout, leads to an increase in travel distance, which increases the dependence on motorized travel, and the pace of private cars entering the family will gradually accelerate.

The pressure on urban roads is increasing, and the high travel rate of cars during peak traffic hours will directly lead to road traffic congestion.

Gasoline price increases, traffic jams, etc., when they realize that driving is not good for the environment, they can be conscious, or reduce the cost of taking the bus, and the state will do more public service advertising.

It will cause a big traffic problem. The convenience of private transportation comes at the cost of high consumption of road resources, and the spatio-temporal resources of the road occupied by two cars are about equal to one bus, but its carrying capacity is less than 1 5 of the buses.

For example, traffic congestion and other traffic problems, and the time to the destination is shortened, and the time to the end of life is also shortened.

Traffic jams. Travel feels more and more that the original 30-minute bus ride is now delayed by 10 to 20 minutes.

With the outward expansion of urban space and the extension of travel distances, people's dependence on motor vehicles is also increasing.

Answer D Question Analysis: Inertia is an intrinsic property of an object, and its magnitude depends only on the mass of the object; Seat belts are designed to prevent injuries caused by people rushing forward during emergency braking; In ice and snow days, the friction is reduced because the road surface is icy, so in order to increase the friction, snow chains can be installed on the tires; The braking distance of the car depends on the running speed of the car and the reaction time of the person, and the reaction time of the drunk person increases, so it can be analyzed why the drunk driving can not be drunk a, inertia is the inherent property of the body, and the inertia has nothing to do with the speed; The purpose of limiting the speed is to reduce the braking distance, so a is wrong;

B. According to the inertia, it can be known that the person is leaning back when starting suddenly, and the seat belt does not have any effect, so B is wrong;

c. The snow chain can increase the friction between the wheel and the ground to prevent traffic accidents, so C is wrong;

d. After drinking, due to the slower reaction, the reaction time becomes longer, and the braking distance becomes larger, which is very easy to cause traffic accidents.

Therefore, choose the D test point: This question tests inertia, physical knowledge, and methods of increasing or decreasing friction.

Comments: When all objects are not affected by external forces, the property of always maintaining a uniform linear motion or a state of rest is inertia, so Newton's first law is also called the law of inertia The understanding of inertia should pay attention to the following four points: (1) All objects have inertia (2) Inertia is an inherent property of an object (3) Mass is the only measure of the magnitude of inertia (4) Inertia is a property of an object, not a force

1) The reversing radar works by using the principle of ultrasonic;

2) The optical path of light is reversible in both refraction and reflection;

3) After opening the car window, by speeding up the flow of air, the evaporation of sweat is an endothermic process, that is, the evaporation of sweat will absorb the heat of the human body, so it will feel cool

ts=vt=340m/s×

So the answer is: (1) ultrasound; (2) reversible; 3) After opening the car window, by speeding up the flow of air, the evaporation of sweat is an endothermic process, that is, the evaporation of sweat will absorb the heat of the human body, so it will feel cool(4) The distance between the car and the obstacle is approximately.

a. Inertia is an inherent property of an object, and the magnitude of inertia has nothing to do with the magnitude of velocity; The purpose of limiting the speed is to reduce the braking distance, so a is wrong;

b. After drinking, due to the slower reaction, the reaction time becomes longer, and the braking distance becomes larger, which is easy to cause traffic accidents, so it is correct;

c. The snow chain can increase the friction between the wheel and the ground to prevent traffic accidents, so it is wrong;

d. According to the inertia, it can be seen that the person leans back when it is suddenly started, and the seat belt does not have any effect, so it is wrong;

Therefore, choose B