known that the Earth attracts any body to its core by the so-called gravitational field .This means that the greater the distance between the body and the surface of the planet, the earth with greater force acts on it, and the more pronounced gravity.
on body falling vertically downward, it is still affected by the aforementioned force, due to the action which the body is sure to fall down.It remains an open question as to what will be its speed in the fall?On the one hand, subject to influence of air resistance, which is sufficiently strong, the other - the body is strongly attracted to the earth than it is from her next.The first - obviously will be an obstacle and reduce speed, the second - to give acceleration and increase speed.Thus, there is some question as to whether it is a free fall on Earth?Strictly speaking, the free fall of the body is possible only in a vacuum, where no interference with the resistance of air flow.However, in modern physics, the free fall of the body is considered to be vertical movement, which does not meet the noise (air resistance can be ignored in this case).
The thing is that to create conditions where the falling object is not affected by other forces, in particular, the same air, we can only artificially.It has been experimentally proved that the velocity of free fall of the body in a vacuum is always the same number regardless of body weight.This movement is called uniformly accelerated.It was first described by the famous physicist and astronomer Galileo Galilei more than 4 centuries ago.The relevance of these findings has not lost its power to this day.
As already mentioned, the free fall of a body in the framework of everyday life - it is conditional, and is not quite correct name.In fact the speed of the free fall of a body is not uniform.The body is accelerated, whereby such a movement described as a special case uniformly accelerated motion. In other words, every second speed of the body will change.Due to this reservation, it is possible to find the speed of free fall of the body.If we do not give the subject of acceleration (ie, do not throw it, but simply omitted from a height), its initial velocity is zero: Vo = 0.With every second the rate will increase in proportion to the elapsed time and speed: gt.
It is important to comment on the input variable g.This - the acceleration of gravity.Previously we have already noted the presence of accelerating the fall of the body under normal circumstances, i.e.in the presence of air and under the influence of gravity.Any body falls to the ground with the acceleration equal to 9.8 m / s2, regardless of its weight.
Now, referring to the reservation, we derive a formula that will calculate the speed of the free fall of the body:
V = Vo + gt.
ie the initial velocity (if we gave her body through throwing, pushing or otherwise manipulate) adding the product of the acceleration of free fall on the number of seconds it took the body to reach the surface.If the initial velocity is zero, the formula takes the form:
V = gt.
That is simply the product of the acceleration of free fall for a while.
Similarly, knowing the speed of free fall object, you can display the time of his movements or the initial rate.
should also distinguish between the formula for calculating the velocity of a body thrown at an angle to the horizon, as in this case will act forces, gradually slowing the velocity of a thrown object.
In the case considered by us, the body of the only force of gravity and air resistance that, by and large, the change does not affect the speed.
