When a stick floats vertically in water, it is subject to the action of two main forces: buoyancy and gravity. Buoyancy is the upward force exerted by an object in a fluid (such as water) and is related to the volume of the object and the density of the fluid. Gravity is the downward force exerted on an object and is related to the mass of the object.
When the stick floats vertically, buoyancy and gravity are balanced. This means that the weight of the water displaced by the stick (i.e. the pushing force) is equal to the weight of the stick itself. Since the density of the water is greater than the density of the stick, the stick will float on the water.
When you hang a heavy object under the wooden stick, the gravity of the water displaced by the wooden stick will increase, but the gravity of the wooden stick itself will also increase accordingly (because the mass of the heavy stick (the object is added to the mass of the stick). If the total mass of thestick and weight is always less than the mass of water displaced by the stick, so the stick and weight will always float. In this case, the buoyancy and gravity forces exerted on the stick and the weight as a whole are always equal, so they can remain vertically buoyant.
However, if the weight is too heavy, such that the total mass of the stick and the weight are greater than the mass of water displaced by the stick, then the stick and weight will not be able to continue to float. In this case, the sticks and weights will sink in the water.
A heavy object is pulled from the bottom of the buoy and submerged in the water. There is air and water in the buoy. Why is the gravity of the weight below not added when calculating the gas pressure in the buoy. buoy?
《Fishing “The iron ox” is an article in a primary school textbook. He only talks about how to use scientific methods andintelligent to recover an iron ox. However, the article does. I do not describe how the iron ox fell into the river and went upstream.
The true story of heavy objects falling into the river and moving upstream comes from an article "Stone Beasts in the River" in Volume 16 "Guwan Tingzhi" of "Notes on the Cottage Yuewei" by Ji Xiaolan of the Qing. Dynasty. Two stone beasts fell into the river and were not found where they fell or downstream. Finally, under the leadership of the professor and the old river soldier, the stone beasts were found in the upper reaches of the river. Many people will ask questions: How well does this story conform to the scientific principles of heavy objects falling into the river and moving upstream?
1. The scientific nature of the iron ox (stone beast) falling into the riverre and walking upstream. The iron ox (stone beast) fell into the soft river bed, forming resistance to the river water. The fast water of the river would inevitably impact the iron ox (stone beast), so when the iron ox (stone beast) and. The river water touched, a whirlpool was formed at the place, and the whirlwind gradually took away the soft sand under Tieniu (the stone beast), and slowly formed a pit in front, and Tieniu rolled in forward into the pit. This situation happens again and again, and the iron bull will continue to circle upstream, running upstream as if it has legs, and will not stop until it is completely buried in the silt. This phenomenon is therefore actually a physical phenomenon and is consistent with scientific principles.
2. The conditions for an iron ox (stone beast) to fall into the river and swim upstream. Of course, this phenomenon does notIt is not suitable for all situations and must meet certain conditions. First of all, heavy objects must beIt is large and heavy and cannot be carried away by the force of the river water. Second, the river bed must be soft enough, such as sand, gravel or dirt. If it is a solid cement floor and the river water cannot wash the cement floor into the pits, this phenomenon will not occur. Therefore, there are certain conditions for an iron ox (stone beast) to fall into a river and move upstream. For example, if two heavy objects, an iron ox and a stone beast, fall into the river, they must rise again. There is nothing wrong with that and it is scientifically consistent.
In fact, even a fully sealed rigid "buoy" will be "compressed" in volume under the high water pressure of deep water, resulting in an eventual reduction in internal space. The pressureinternal air pressure is low and the internal air pressure increases. Therefore, the research and development of “Jiaolong” deep submersible is a high-tech problem that solves the impact of strong external pressure.
The "buoy" mentioned in the question is equivalent to a "diving bell". There is air inside and water can enter directly into the diving bell or sinking "pull". external heavy objects only Since the "diving bell" can overcome buoyancy and maintain a certain position in the water, it only allows the diving bell to overcome the influence of buoyancy, while its internal air pressure increases to maintain balance with external pressure (water pressure at the water depth where it is located). Nothing to do with himself or the counterweight.