Absolutely all bodies in the Universe are affected by a magical force that somehow attracts them to the Earth (more precisely, to its core). Nowhere to escape, nowhere to escape from a comprehensive magical attraction: the planets of our solar system are attracted not only to the huge Sun, but also to each other, all objects, molecules and tiny atoms are also mutually attracted. Isaac Newton, known even to young children, having devoted his life to the study of this phenomenon, established one of the greatest laws - the law of universal gravitation.
What is gravity?
The definition and formula have long been known to many. Recall that gravity is a certain quantity, one of the natural manifestations of universal gravitation, namely: the force with which every body is invariably attracted to the Earth.
Gravity is denoted by the Latin letter F heavy.
Gravity: Formula
How to calculate gravity directed at a specific body? What other quantities do you need to know in order? The formula for calculating gravity is quite simple, it is studied in the 7th grade of a comprehensive school, at the beginning of a physics course. In order not only to learn it, but also to understand it, one should proceed from the fact that gravity, invariably acting on the body, is directly proportional to its quantitative value (mass).
The unit of gravity is named for the great scientist — Newton.
Gravity (gravity) is always directed strictly down to the center of the earth’s core, thanks to its effect all bodies equally fall down. We observe the phenomena of gravitation in everyday life everywhere and constantly:
- objects accidentally or specially released from hands must fall down to the Earth (or to any surface that prevents free fall);
- a satellite launched into space does not fly away from our planet an indefinite distance perpendicular upwards, but remains to rotate in orbit;
- all rivers flow from the mountains and cannot be reversed;
- it happens that a person falls and gets hurt;
- the smallest specks of dust sit on all surfaces;
- air is concentrated at the surface of the earth;
- heavy to carry bags;
- rain is dripping from clouds and clouds, snow is falling, hail.
Along with the concept of "gravity" the term "body weight" is used. If the body is placed on a flat horizontal surface, then its weight and gravity are numerically equal, thus, these two concepts often replace, which is not at all correct.
Acceleration of gravity
The concept of “acceleration of gravity” (in other words, the gravitational constant) is associated with the term “gravity”. The formula shows: in order to calculate the force of gravity, you need to multiply the mass by g (acceleration sv.p.).
"g" = 9.8 N / kg, this is a constant. However, more accurate measurements show that due to the rotation of the Earth, the acceleration value of St. n. is not the same and depends on latitude: at the North Pole it = 9.832 N / kg, and at the sultry equator = 9.78 N / kg. It turns out that in different places of the planet different gravity is directed at bodies of equal mass (the formula mg still remains unchanged). For practical calculations, it was decided not to pay attention to minor errors of this value and use the average value of 9.8 N / kg.
The proportionality of a quantity such as gravity (the formula proves this) allows you to measure the weight of an object with a dynamometer (similar to a normal household business). Please note that the device only shows strength, because to determine the exact body weight you need to know the regional value of "g".
Does gravity act at any (both close and far) distance from the earth's center? Newton hypothesized that it acts on the body even at a considerable distance from the Earth, but its value decreases in inverse proportion to the square of the distance from the object to the core of the Earth.
Gravity in the Solar System
Is there gravity on other planets? The definition and formula for other planets remain relevant. With only one difference in the meaning of "g":
- on the moon = 1.62 N / kg (six times less than the earth);
- on Neptune = 13.5 N / kg (almost one and a half times higher than on Earth);
- on Mars = 3.73 N / kg (more than two and a half times less than on our planet);
- on Saturn = 10.44 N / kg;
- on Mercury = 3.7 N / kg;
- on Venus = 8.8 N / kg;
- on Uranium = 9.8 N / kg (almost the same as ours);
- on Jupiter = 24 N / kg (almost two and a half times higher).