Question

b. Write a short paragraph based on the hints given below
Air Transport - Mobility of men and material - by air - First flight - American Wright brothers
- 1903- Gift of 20th Century - developed in last 60 years - key element in country's
infrastructure - tough competition to railways - fastest means -comfortable and quick service
- useful for long distances - Unbroken journey over land and sea - free from physical barriers
- saves time - strategic importance - used for internal and external security - helps in space
exploration- used for rescue operations - vital role in times of emergency - Disadvantages -
costly service - large investment -
large investment - costly to construct and maintain -uncertainty and
unreliable - greater risks - prone to accidents - Hijacking of planes - small carrying capacity
Unsuitable for carrying - heavy goods.​

Answer 1

Explanation:

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From ancient times men have wanted to fly, and many attempts were made before suitable methods were discovered. The first really successful method to be developed was the balloon, filled with light gases such as hydrogen or helium which, being lighter than air, were able to rise above the surface.

Apart from controlling the altitude of flight by releasing gas or lessening the amount of ballast carried, balloons were dependent for their general direction upon winds and air currents. Later types of balloons had rudders and steering devices.

At the end of the nineteenth century rigid airships, with a solid framework rather than a simple bag of gas were developed, and these were powered by internal combustion engines. Airships were the first aircraft to cross the Atlantic, but they proved difficult to handle and were generally an un­satisfactory method of transport, and were not used after the 1920s.

Gliders, utilizing air currents and capable of carry­ing men were developed in the late nineteenth century and were the forerunners of powered aircraft or aeroplanes. The first successful flight by aeroplane was by the American Wright brothers in 1903, and since that time great developments have revolution­ized air transport.

Aircraft engines underwent radical alterations as gas turbines, turbo-props and then jet engines were developed, and other features such as pressurized cabins, safety devices, and remote-control landing devices for use in poor weather conditions have also greatly improved aircraft. Vertical take-off and landing, as in helicopters, has also been, evolved.

Air transport is relatively independent of physical barriers such as mountain ranges, though of course, this depends to a large extent on the size and range of the aircraft employed. While the larger jets can fly at great heights, avoiding all barriers, smaller planes have a shorter flight range and must fly at lower altitudes. Such small planes, however, which fly along valleys and between the mountains are extremely important for easing internal transport, e.g. in Nepal or the Andes. Aircraft of one type or another have made it possible to reach the most remote parts of the earth.

For long-distance travel aircraft are by far the fastest and most efficient method of passenger transport. By the late 1920s passenger planes were already flying at more than 160 kilometres per hour (100 m.p.h.). Jet aircraft can nowadays fly at speeds faster than sound, i.e. at 1,056 k.p.h. (660 m.p.h.) at an altitude of 10,970 metres (36,000 ft) and regular air services operate at speeds around 800 k.p.h. (500 m.p.h.).

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Despite the rapid rise of air transport for passengers, the growth of air-freight traffic was for a long time much slower. This is because air transport is relatively expensive and is only used for cargo either when speed is essential, as in the case of perishable goods, urgently- required medical or food supplies, or where the high value of the goods offsets the high cost of transport, as in the case of luxury goods.

Nevertheless goods traffic by air is on the increase and has grown rapidly in the last decade. While passenger traffic has tripled, freight traffic has quadrupled. It is still not large by comparison with other modes of transport, however. One specialized role played by air­craft is in the relief of major disasters when land transport is unable to reach the areas. In the case of wars, earthquakes, floods and so on, medical supplies, food, and rescue personnel can be quickly airlifted to affected areas.

Commercial airlines came into being after the First World War, the first regular air-service being between London and Paris in 1919. The earliest countries to operate airlines were Britain, France and the U.S.A., where the first planes were developed, but since the Second World War a very large number of airlines has come into operation.

An airline is now a national prestige and status symbol and almost every country in the world has at least one airline. In countries such as the U.S.A. and Britain there are several major companies. The world is now spanned by a vast net­work of air-routes, though the density of the routes and the frequency of services varies very much from one part of the world to another, depending on the availability of suitably equipped airports, refuelling facilities, as well as on the potential demand for air services.

Airlines can only run economically if there are sufficient passengers to fill regular flights to near-capacity. This in turn depends on the standard of living, for air fares are generally very high compared with those of ocean or land transport.