перевести текст. Centre of gravity.We know to act on every particle

Перевести текст.
Centre of gravity.
We know to act on every particle of a body so that its weight is actually distributed throughout the body. But a solid body has one point at which it can be supported by a single upward force. In other words,the whole weight of a body acts as though it is concentrated at a single point and this point is called the centre of gravity.
If you are asked to carry a heavy object in one хэнд, you automatically take it up at the centre of gravity. If it begins to tip, when you first take it up, you move your хэнд along the object to the centre of gravity. The location of the centre of gravity of a uniform body is known to depend on its size.
STABILITY A book lying on a table is expected to keep its position without any difficulty, as one knows it to be in a state of equilibrium.However, to make it stand on end is not easy at all.In the same way, a pencil will lie on the table without any tendency to tip over. With some difficulty one can make it stand on its unsharpened end but will not stand at all, alone, upon its sharp end
The stability of an object is measured by the amount of work to be required to make it a new position. The stability of an object is greatest when its centre of gravity is at the lowest level. That is why, to increase the stability of a motor-car, its designer tries to keep the centre of gravity as low as possible