Absolutely all bodies in the Universe are affected by a magical force that somehow attracts them to the Earth (more precisely, to its core). There is nowhere to escape, nowhere to hide from the all-encompassing magical gravity: the planets of our solar system are attracted not only to the huge Sun, but also to each other, all objects, molecules and the smallest atoms are also mutually attracted. Isaac Newton, known even to small children, having devoted his life to studying this phenomenon, established one of the greatest laws - the law of universal gravitation.
What is gravity?
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 any body is invariably attracted to the Earth.
Gravity is denoted by the Latin letter F heavy.
Gravity formula
How to calculate the force of gravity directed to a certain body? What other quantities do you need to know in order to do this? 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 the force of gravity, invariably acting on a body, is directly proportional to its quantitativesize (mass).
The unit of gravity is named after the great scientist Newton.
Gravity (gravity) is always directed strictly down to the center of the earth's core, due to its influence all bodies fall down with uniform acceleration. We observe the phenomena of gravity in everyday life everywhere and constantly:
- objects, accidentally or specially released from the hands, necessarily fall down to the Earth (or to any surface preventing free fall);
- a satellite launched into space does not fly away from our planet for an indefinite distance perpendicularly upwards, but remains in orbit;
- all rivers flow from mountains and cannot be reversed;
- sometimes a person falls and gets injured;
- tiny dust particles settle on all surfaces;
- air is concentrated at the surface of the earth;
- hard to carry bags;
- rain drips from clouds and clouds, snow falls, hail.
Along with the concept of "gravity" the term "body weight" is used. If a body is placed on a flat horizontal surface, then its weight and gravity are numerically equal, so these two concepts are often substituted, which is not at all correct.
Free fall acceleration
The concept of "acceleration of free fall" (in other words, the gravitational constant) is associated with the term "force of gravity". The formula shows: in order to calculate the force of gravity, you need to multiply the mass by g(acceleration of St. p.).
"g"=9.8 N/kg, this is a constant value. However, more accurate measurements show that due to the rotation of the Earth, the value of the acceleration of St. p. is not the same and depends on latitude: at the North Pole it is=9.832 N / kg, and at the sultry equator=9.78 N / kg. It turns out that in different places on the planet, different gravity forces are directed to bodies with the same mass (the formula mg still remains unchanged). For practical calculations, it was decided not to pay attention to minor errors in this value and use the average value of 9.8 N/kg.
The proportionality of such a quantity as gravity (the formula proves this) allows you to measure the weight of an object with a dynamometer (similar to ordinary household business). Please note that the meter only displays force, as the local "g" value is required to determine the exact body weight.
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 inversely with the square of the distance from the object to the Earth's core.
Gravity in the solar system
Do other planets have gravity? The definition and formula regarding other planets remain valid. With only one difference in the meaning of "g":
- on the Moon=1.62 N/kg (six times less than on Earth);
- on Neptune=13.5 N/kg (almost one and a half timeshigher 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 Uranus=9.8 N/kg (almost the same as ours);
- on Jupiter=24 N/kg (almost two and a half times higher).
