How can physical buoyancy be good, and why is buoyancy so difficult to learn?

Understand Archimedes' principle first, as long as you work hard, I believe you can do better

Many people say that buoyancy is difficult to learn not because of buoyancy itself, but because buoyancy is very comprehensive. He can combine many other physical knowledge, especially statics and force analysis. Moreover, the general calculation questions are comprehensive questions.

If you want to learn buoyancy well, you have to start from many aspects.

Balance of two forces:

Whether or not to use two-force equilibrium to explain a buoyancy problem, we must first look at the state of the object in the water. In water, it is forbidden to keep it forbidden, or to descend at a uniform speed, which is a state of equilibrium, which can be explained by the balance of two forces.

If the object is not balanced, then use Archimedes, f = liquid density x g x v row.

Submarine: When the submarine does not move in the water, or moves in the horizontal direction (there is no movement in the vertical direction), then it is subjected to a balanced force in the vertical direction, that is, the buoyancy is equal to the gravity, at this time, if it wants to descend, then it absorbs water to increase its gravity, so as to break the balance of the two forces and fall. In the same way, when it wants to rise, it drains water outward, reduces its own gravity, breaks the balance of the two forces, and the buoyancy is greater than the gravity, and rises upward.

The object we are talking about in the water without the action of other external forces, it can only show a state, either sinking, or floating, or levitating, once it wants to change the state, it has to be subjected to external force, just like a submarine, the external force is just the gravity of the water that is sucked in or discharged.

As for paper balls, you can think of water as dirt. A table has four legs, put the table on the dirt, it will not sag, but you try to turn the table into one leg, it will definitely sink, which is to change the contact area between objects. Once the bottom area of the paper ball in contact with the water becomes larger, it will inevitably increase the volume, resulting in a larger volume of water discharged, which in turn will cause buoyancy equal to gravity and float on the surface of the water.

Hehe.. I feel the same way. We're talking about buoyancy right now, too.

Although it is a little more difficult than before, in fact, you can still learn this little thing in junior high school by listening carefully. If you want to improve your score, go ahead and brush the questions. Physics is still about thinking.,See if you still love to think.,When you don't understand, ask the teacher.,The teacher likes to love the students.。。。

The questions you have above are all theoretical, and the teacher can understand them as soon as they talk about it.

Of course, the buoyancy part is not simple, it contains a lot of knowledge and is more complicated. To learn it well, you have to master the basics, think a lot, and try to open your mind as much as possible. But don't worry too much, because that part is really difficult, we always say that the depth and number of investigations have become smaller, so don't worry if you don't grasp it well, the most important thing is to be normal, come on!

It is to understand how the force of buoyancy is generated, although there are floating, levitating, and sinking to the bottom, but the principle of generation is the same. There is pressure at various points below the liquid level, and buoyancy is generated by the pressure difference. The finale of the physics high school exam is a comprehensive question of pressure and buoyancy.

For example, a cube with both sides and length A is submerged in water, and the upper and lower surfaces are subjected to different pressures from the water, but in fact, the sides are also subjected to pressure, but they are only offset. The internal pressure of the liquid is PGH, the pressure difference is PGA, and the pressure difference is PGA·a·a=PGA=PVG, which explains why there is a V row.

If you know how to swim, please go to the pool and experience it, I believe it will give you a lot of insight, so that you can deeply understand the principles of buoyancy and the physical meaning of the formula.

When floating, float with f = g object.

When submerged, float with f = liquid * g * v discharge.

When the submerged volume is the same, the object and the liquid are compared》 The liquid sediments < the liquid floats, that is, the gravity of the object is compared.

Hope it helps.

Buoyancy is equal to the gravitational force exerted by the water dislodged by the object.