If to neglect air resistance, time of falling of a body does not depend on its weight. It is defined only by height and acceleration of gravity. If to dump two bodies of different weight from identical height, they will fall at the same time.

## It is required to you

- - calculator.

## Instruction

1. Transfer height from which the body falls to SI units - meters. Acceleration free falling is given in the reference book already transferred to units of this system - the meters divided into seconds in a square. For Earth on a midland it makes 9.81 m / ^{с2}. In the conditions of some tasks other planets, for example, of Long (1.62 m / ^{с2}), Mars are specified (3.86 m / ^{с2}). When both initial sizes are set in SI units, the result will turn out in terms of the same system - seconds. And if in a condition the body weight is specified, ignore it. It is information superfluous here, it can be provided to check, how well you know physics.

2. For calculation of time of falling of a body increase height by two, divide into acceleration of gravity, and then take a square root from result: t= √ (2h/g) where t is time, with; h - height, m; g - acceleration of gravity, m / ^{с2}.

3. The task can demand to find additional data, for example, on what was body speed at the time of contact of the earth or at a certain height from it. Generally calculate speed so: v= √ (2g (h-y)) are entered new variables Here: v - speed, m/s and y - height where it is required to learn the speed of falling of a body, m. It is clear, that at h=y (that is, at the initial moment of falling) speed is equal to zero, and at y=0 (at the time of contact of the earth, before the stop of a body) the formula can be simplified: v= √ (2gh) After the contact of the earth already happened, and a body stopped, the speed of its falling is equal to zero again (if, of course, it did not spruzhinit and did not jump up again).

4. For reduction blow forces after the end of free fall are used by parachutes. In the beginning fall is free and happens according to the equations given above. Then the parachute is developed, and there is a smooth delay at the expense of resistance of air which cannot be neglected now. The regularities described by the equations given above do not work any more, and further reduction of height happens slowly.