To determine building height, it is possible having risen by its roof and having lowered from it a long cord with cargo to the Earth's surface. Length of a cord then can be measured on the earth. If it is not possible to make it, measure house length, using the angle meter or the shadow cast by sunshine.
It is required to you
- - thin strong cord;
- - cargo;
- - angle meter;
- - roulette.
Instruction
1. Rise by the top point of the building with a hank of a thin and strong cord to which end the cargo sufficient is attached in order that did not take down a cord wind. From this point lower cargo on the Earth's surface, watching that the cord was perpendicular to the Earth's surface. A marker note cord length when cargo falls by the earth. After that go down and by means of a roulette measure length of the lowered cord. It will also be house height.
2. If it is impossible to measure house height in such a way, take the angle meter, and direct it from the Earth's surface to the top point of the building. Measure a corner which is formed between the Earth's surface and the direction on the top point of the building. From that point where the angle meter was installed, measure distance to the bottom of the building by means of a roulette or a laser range finder. To measure house height, find the work of the measured distance on a tangent of angle under which it is visible a top of the building of h=L • tg(α).
3. For determination of height of the building, cut out an equal lath which height is in advance measured. Establish a lath strictly perpendicular to the Earth's surface near the building so that it cast a shadow (you perform measurement sunny day when objects cast an accurate shadow). For determination of perpendicularity you will use the construction plumb representing the weight on strong thread (it is possible to use a thick fishing line). By means of a roulette measure length of a shadow which is cast by a lath. Then measure length of a shadow which is cast by the building.
4. To find height of the building find the work of height of a lath at length of the shadow cast by the building, and divide into height of the shadow cast by H= lath (h•L)/l. Where H is height of the building, h is lath height, L – length of a shadow of the building, l – lath shadow length. If there is no suitable lath, as a standard use own growth.