Mention the concept of free-fall acceleration often accompanied by examples and experiences from school textbooks, within which different weight objects (such as a pen and coins) were dropped from the same height.It seems absolutely clear that the objects fall to earth at different time intervals (pen so generally can not fall).Consequently, the free fall of bodies is not subject to only one specific rule.However, it seems self-evident only now, some time was required to conduct tests to confirm this.Researchers reasonable to assume that in the fall of bodies operating a power that affects their movement and, as a consequence, the rate of vertical movement.This was followed by no less famous experiments with glass tubes with inside a coin and pen (for the purity of the experiment).From tube was exhausted air, after which they were tightly sealed.What was the surprise of researchers, when and pen and coins, despite the obviously different weights fall at the same speed.
This experience was the basis not only for the creation of the concept of
So the notion gravitational acceleration , received the following definition:
- bodies falling from rest under the influence of Earth's gravity.
This concept was awarded the letter of the Greek alphabet g (PVCs).
On the basis of these experiments, it became clear that the USP exactly typical of the Earth, since we know that our planet is a force that attracts all the surface of the body.There was, however, another question: how to measure the value and what it equals.
decision to the first question was found rather quickly: scientists with a special photographic fix the position of the body during the fall in a vacuum at different time intervals.It turned out an interesting thing: all the bodies in the Earth's fall with the same acceleration, which, however, varies somewhat depending on the location on the planet.The height at which the body began to move, does not matter: it can be 10, 100 or 200 meters.
was possible to find out: the acceleration of gravity on Earth is approximately 9.8 N / kg.In fact, this value may also be in the range from 9.78 N / kg to 9.83 N / kg.This difference (albeit small in the eyes of the layman) explains how the shape of the Earth (which is not quite spherical, but flattened at the poles) and the daily rotation of the Earth around the sun.Typically, the average value of counts taken - 9.8 N / kg for large numbers - rounded up to 10 N / kg.
g = 9,8 N / kg
Against the background of the data shows that the acceleration due to gravity on other planets thereof different from the world.Scientists came to the conclusion that it can be expressed by the following formula:
g = G x M planet / (R planet) (2)
simple words: G (gravitational constant (6,67 • 10 (-11)m2 / s2 ∙ kg)) must be multiplied by M - mass planet-divided by R - radius of a planet in the square.For example, find the acceleration of gravity on the moon.Knowing that its mass is equal to 7.3477 × 10 (22) kg, and the radius - 1737.10 km, we find that USP = 1.62 N / kg.As you can see, the acceleration in the two planets are very different from each other.In particular, in the world, it is almost 6 times as much!Simply put, the moon draws objects that are on the surface, with a force of less than 6 times than the Earth.That's why the astronauts on the moon, we see on television, like it becomes easier.In fact, they lose weight (not mass!).The result is a funny effects like jumping several meters, the feeling of flying and long steps.
