Measure the height of tall buildings, how to measure the height of a building

The change in the velocity of the ball is negligible compared to its instantaneous velocity at this time, so the motion in this very short period of time can be treated as a uniform motion According to the formula of average velocity, the velocity at the time of landing is calculated, and then the height of the building is found according to v2=2gh

Answer: Solution: Let the velocity of the ball at the lower end of the rope when it hits the ground be v, then the velocity of the ball at the upper end is also v, so there is: l divided by v

t again by: v2=2gh

Solution and substitute the number to obtain: h=80m

If the formula is written as V2=2GH (H-1), the result is 81m, so the height of the building is 80m or 81m

The 8 methods are as follows:

1. For rectangular buildings, you can choose certain angles to make the building look like a square. Make a note of the location and measure the length of the bottom edge of the building.

2. Or this bamboo pole, insert it in a suitable place, lie on the ground to look at the bamboo pole head, and find that the bamboo pole head coincides with the top of the building. Measure the distance between the eyes and the bamboo pole and the distance from the building.

3. To measure the length of the shadow of the building, you need to find a dog-beating stick, or a bamboo pole, and insert it on the ground, and measure the length of the bamboo pole and the shadow of the bamboo pole with a ruler. The shadow length of the building can be measured by walking and steps.

4. Or this bamboo pole, put it horizontally on the top floor, roll it into a thin tube with paper, stand on the ground and look at the bamboo pole from the tube with one eye, and retreat to a suitable place to make the bamboo pole look like the diameter of a thin paper tube. Then stick the bamboo pole on the ground, stand in the appropriate place and look at it again with the paper tube until you see the same effect.

5. Observe any repetition of the exterior wall of the building.

patterns, such as mosaics.

Glass curtain wall. Sections of sewer pipes. The length of each pattern is then measured, multiplied by the number of repetitions.

6. Use a barometer to measure the atmospheric pressure on the ground and the roof.

This difference in atmospheric pressure can then be used to calculate the height of the building.

7. Take the barometer to the top of the building, bend down and let go of the barometer, and at the same time use the computer to measure the time it takes for the barometer to fall to the ground, the height of the building is equal to one-half times the acceleration of gravity.

Multiply by the square of time.

8. Climb the stairs with the barometer, mark the height of the barometer along the wall, mark it until the top floor, see how many marks, and then multiply it by the height of the barometer, which is the height of the building.

1. Measure the length of the shadow of a tall building, and at the same time determine the angle of sunlight (solar angle).

2. Erect two poles of different heights, see how far the distance is, the top of the pole and the top of the high-rise building are 3 points in a line, measure the height of the pole, the distance between the pole and the building, and the distance between the poles.

3. Put the rope from the roof and measure the length of the rope.

4. Throw a stone from the roof of the building to determine the landing time.

5. Count the floors and determine the height of one floor. (Applicable to the same floor height).

6. Use surveying and mapping equipment to measure the angle of view of the equipment on the roof of the building, and record the distance between the height of the equipment and the high-rise building.

7. Ultrasonic reflection method, from the roof to the ground, the reflection time is calculated. (You can go up from the bottom, and you need to have a reflective surface on the top.) ）

A long, long time ago, in Cairo, the capital of ancient Egypt, the Egyptian pharaoh wanted to find the smartest man in the world to measure the height of the pyramids, and he asked Thales what tools he would use to measure the height of the pyramids, and Thales said that he would only use a ruler. He stood beside the pyramid, and when the length of the shadow was equal to his height, he measured the length of the shadow of the pyramid and half the length of the bottom edge, and added them up to the height of the pyramid.

When the three corners of two triangles are equal, the ratio of their equal side lengths can form a proportion, which is called a similar triangle.

Today, we can still measure the height of a building in the Taylors way. Prepare a length of tape measure to make sure the measuring site is open and as close to the building as possible. Using your height as a reference, measure the shadow length of the building when the shadow is the same as your height, at which point its shadow length is equal to its height.

Let's analyze that light travels in a straight line. When we stand in the sun, our body and our shadow are at right angles, and our body and shadow are right angles, and the light rays are hypotenuses, and they form a triangle between them. The same is true for buildings, when our height and shadow length are the same, and the buildings at the same time are shadowed by rays of rays parallel to the rays that form our shadows, then they form a similar triangle with each other, and the shadow length of the building coincides with its actual height.

But there is a question, is it possible that the rays emitted by the same light source are parallel? Please think carefully about this question, if the light received by the building and the light we receive come from the same light source——— the sun, if the two rays are not parallel, then they will not form similar triangles, and the measured results will not be accurate. Why, exactly?

I believe that you will soon have the answer, if you know the answer, please tell me in QQ, if you think it's too simple, it's okay if you don't want to say it.

Four Methods:

1. You can use a ruler to measure the height h of each staircase, and then count the number of stairs from the first floor to the floor n, then its height = nh.

2. Tie a heavy object with a long enough rope, lower it from the roof, and then use a ruler to measure the length of the rope is the height of the building.

3. Use the projective theorem to solve it (projection method).

4. Take something and put it on the roof, let it fall freely, and then go through the time and formula of falling to the ground.

y=1/2 gt^2

Calculate the distance.

Then pay attention to the effect of the speed of sound to be subtracted.

The floor height of a building is the vertical distance between the structural elevation of the upper and lower floors (or ground to floor), where the floor height of the top floor is the vertical distance from its floor to the structural elevation of the roof (lowest point). Therefore, when the owner measures the floor height of the building, he should pay attention to the thickness of the floor slab, otherwise the net height of the house is measured. Floor height = clear height + floor thickness.

1. The measurement basis and method of "building and people". The teaching building is a physical object, with an actual height and a shadow length; People have height, the same is the real thing, there is also a shadow length, measure the height of the person, the shadow length and the shadow length of the teaching building, and list the proportional formula to calculate the height of the teaching building.

2. The measurement basis and method of "building and bamboo pole". The principle is similar to the first group, using the bamboo poles prepared in advance, move the bamboo poles back and forth on the shadow of the teaching building, until you see that the shadow of the bamboo pole coincides with the top of the teaching building of the flagpole.

3. Measurement basis and method of "Reflection Principle of Light". According to the principle of reflection of light, students place a mirror on the ground at a distance from the school building, and then move back and forth until they see the top of the school building in the mirror.