Укажите, каком из перечисленных случаев не совершается механическая работа?

the united kingdom of great britain and northern ireland is situated on the british isles.the country’s shores are washed by the atlantic ocean, the north sea and the irish sea. the english channel separate great britain from the continent.the capital of the united kingdom is london, in england. the capitals of scotland, ireland and wales are edinburgh, belfast and cardiff respectively. great britain is the fourth most populous country in europe, it has about 57 million inhabitants.although a small island, great britain has a remarkable variety of landscapes. to the north and west are highlands — the mountains of scotland, cambria and wales, and the pennine chain. to the east are flat plains, and in the south are lowlands broken by low ranges of hills. to the southwest are the bleak moors of devon and cornwall. a warm ocean current, the gulf stream, washes britain's western shores and accounts for the mildness of its climate.the united kingdom has a temperate climate, with plentiful rainfall all year round.there are many rivers in great britain. the main river is the thames but the longest river is severn.the uk is a parliamentary monarchy. the british parliament consists of two houses: the house of lords and the house of commons. the prime minister is the head of the government.the flag of the united kingdom, known as the union jack, is made up of three crosses. the big red cross is the cross of saint george, the patron saint of england. the white cross is the cross of saint andrew, the patron saint of scotland. the red diagonal cross is the cross of saint patrick, the patron saint of ireland.there are many universities, colleges libraries, museums and theatres in the country. the most famous universities are cambridge university, oxford university, glasgow university.there are many attractions in the uk.in london,for example,there