Gravity: formula, definition

Absolutely on all bodies in the universe the magic force, somehow drawing them to the Earth (more precisely to its kernel) operates. Nowhere to escape, nowhere to hide from the universal magical gravitation: the planets of our solar system are attracted not only to the great Sun, but to each other, all objects, molecules and the smallest atoms are also attracted. Isaac Newton, known even to young children, devoting his life to studying 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 gravity is a certain magnitude, 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.

Gravity: the formula

How to calculate the force of gravity directed to a particular body? What other quantities do you need to know for that? The formula for calculating the gravity is fairly simple, it is studied in the 7th grade of the general education school, at the beginning of the course in physics. In order not only to learn it, but also to understand, one must proceed from the fact that gravity, which invariably acts on the body, is directly proportional to its quantitative value (mass).

The unit of gravity is named after the great scientist Newton.

Gravity (gravity) is always directed strictly downward, toward the center of the earth's core, thanks to its action, all bodies are equally accelerated downward. The phenomena of gravitation in everyday life we observe everywhere and constantly:

• Objects accidentally or specially released from the hands, necessarily fall down to the Earth (or to any surface that prevents a free fall);
• The satellite launched into space does not fly away from our planet indefinitely perpendicularly upwards, but remains spinning in orbit;
• All rivers flow from the mountains and can not be reversed;
• Sometimes a person falls and is injured;
• On the surface there are small particles of dust;
• Air is concentrated near the surface of the earth;
• Heavy to carry bags;
• Clouds and clouds drip rain, snow, hail.

Along with the term "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, so these two concepts are often substituted, which is not at all correct.

Acceleration of gravity

The term "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, it is necessary to multiply the mass by g (acceleration of the STP).

"G" = 9.8 N / kg, this is a constant value. However, more accurate measurements show that, due to the rotation of the Earth, the acceleration value of St. Etc. is not the same and depends on the latitude: at the North Pole it is 9.832 N / kg, and at the hot equator = 9.78 N / kg. It turns out that in different places of the planet on bodies having equal mass, different gravity is directed (the formula, however, remains unchanged). For practical calculations, it was decided not to pay attention to minor errors of this value and to use the average value of 9.8 N / kg.

The proportionality of such a magnitude as the force of gravity (the formula proves this) allows you to measure the weight of an object with a dynamometer (similar to ordinary household business). Note that the instrument only shows strength, since it is necessary to know the regional value of "g" to determine the exact mass of the body.

Does gravity work at any (and near and far) distance from the earth's center? Newton put forward the hypothesis that it acts on the body even at a considerable distance from the Earth, but its value decreases inversely proportional 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 value of "g":

• On the Moon = 1.62 N / kg (six times less than terrestrial);
• 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 Uranus = 9.8 N / kg (practically the same as in our country);
• On Jupiter = 24 N / kg (almost two and a half times higher).