Chapter 2323 (1/2)

Why can't it live on this land or that land? Can't it be that the mother bird living on land here is his wife on the other side?

Nangong warm glanced at Nangong Jin, and saw that he read it calmly. After turning over the paper, he found that all the other places were right. Without any facial expression, he returned the paper to the headmaster.

The teacher, surnamed Zheng, said, ”Nanxu's parents, you have read Nanxu's test paper. I'd like to hear what you think.”

Nangong Jin looks at the teacher Zheng with a strange face.

Mr. Zheng is a middle-aged woman in her 40s, but she is shocked and blushed by Nangong Jin.

”Why, you have nothing to say, right? Do you think Nanxu is wrong, too? If you really think so, I hope you can go back and discipline Nanxu. At least let him understand what it means to respect teachers and teach. ”

Nangong Xu said lightly, ”I can tell from the dispute between you and Nanxu's head teacher just now. This question is yours, so you are very dissatisfied with Nanxu's denial of you. Nanxu is still young, so there is no way to make an analysis from scientific theory. He can only analyze the feasibility of crows drinking water and birds flying over the ocean from the normal state. But I can definitely tell you a formula about buoyancy.

If you want a piece of wood to carry a bird, you need to meet one condition: the buoyancy produced by the wood - the gravity of the wood itself + the gravity of the bird.

In order to make wood play the most role, we assume that wood is just completely stepped below the water surface, so we can draw the conclusion that the density of water * the volume of wood * the acceleration of gravity - the density of wood * the volume of wood * the acceleration of gravity + the weight of birds * the acceleration of gravity. Combine the same terms and simplify them to get: the volume of wood * (the density of water - the density of wood - the weight of birds).

The density of water is about 1000 kg / m3, while the density of wood is between 400 and 750 kg / m3. We can say that when this bird is very clever and finds a lighter one, the density of wood is calculated as 500 kg / m3. It can be concluded that the weight of birds / the volume of wood is - 500 kg / m3.

Simply put, it's the conclusion that if a bird weighs one kilogram, the volume of wood is - 1 / 500 cubic meter - 0.002 cubic meter - 2 cubic meters.