To determine plane flight altitude, observing it from the earth, it is possible only knowing the aircraft speed, and speed - only knowing height. The vicious circle turns out. However the task becomes feasible if to consider that speeds of all passenger planes are approximately identical.
Instruction
1. Make sure that the plane which flight altitude you wish to determine is passenger (other planes fly with the most various speeds) and also that it already gained height and does not decrease yet (it is also impossible to foresee its speed during ascent or decrease).
2. Take aircraft speed for 800 kilometers per hour - approximately with such speed they generally fly. Considering the small accuracy of the method of measurement, it is possible to consider that more exact value of speed is also not required. Take a roulette and extend from it one meter of a tape, place at distance exactly in one meter from eyes (for this purpose it is possible to use the second roulette, or to extend from the only roulette at once two meters, and then to bend a tape at right angle) parallel to the line on which the plane flies, and arrange a row a stop watch. Define for how many seconds the visible image of the aircraft will pass distance from zero before the 100-th division of a roulette.
3. Count what distance during this time the plane flew by actually. In the beginning transfer its speed to meters a seconds for what divide 800 into 3.6. Thus, the plane, most likely, flies with a speed, equal 222, (2) m/s. Then increase this number by time measured by means of a stop watch. It will also be the distance passed by it for this period.
4. It is not necessary to carry out any calculations more! Thanks to the convenient choice of distance from eyes to a roulette and also piece lengths on a roulette (both makes exactly a meter), it is possible to accept result of the previous calculation equal to plane height. If desired try to solve the return problem: knowing that the majority of passenger planes flies at the height about 9000 meters, find flight speed.