The third year of junior high school, physics, buoyancy, boat from the sea to the river

The buoyant force experienced by the object in the liquid = the gravitational force of the discharging liquid = the volume of the discharging liquid * density * g

Obviously, when the ship enters the river from the sea, the gravity of the ship does not change, and the mass of the liquid discharged naturally remains the same, but the density of seawater is greater than that of the river water (because the seawater contains a large number of metal ions, mineral salts and other substances with high molecular mass), therefore, in the case of equal mass, the volume of seawater is less than the volume of river water. Naturally, the ship sank from the sea to the river.

Regardless of whether the ship goes from nautical miles to the river or from the river to the sea, as long as the mass of the ship does not change (it can also be said that the gravity of the ship does not change), the displacement quality (which can also be said to be gravity) will not change. This is precisely because the buoyancy of the object in the liquid = the gravitational force that displaces the liquid, you only need to deepen the concept of the buoyancy of the object, that is, the gravitational force of the liquid that displaces the liquid.

The buoyancy does not change.

It's easy to understand that the ship won't sink anyway, right, that is, it has been in a state of floating, right, and floating is a buoyancy relationship.

F float = G ship, G ship does not change, then F does not change of course.

Also, when floating, you see f float = g boat f float = g row, so these three quantities are all equal, and one of them is unchanged.

Buoyancy = density of liquid * g * volume of displacement.

Buoyancy is equal to its gravity is constant, and it does not matter whether it will sink or not.

The density changes, the volume of drainage changes.

No change: Does the buoyancy change in the floating state?

The buoyancy of the boat from the river to the sea remains the same. The boat is always floating from Hechangzai to the sea, and the buoyancy is always equal to gravity, so the buoyancy remains the same. However, due to the increasing density of the seawater, the V-row should be smaller and the boat should float a little more under the condition of the same buoyancy.

Influencing factors of buoyancy:Buoyancy is related to the volume of the object immersed in the liquid and the density of the liquid. It has nothing to do with factors such as the depth of the object in the liquid, the shape of the object, mass, density, state of motion, etc.

In the junior high school physics experiments, the factor experiment of buoyancy is a very simple and important one, and the important physical concepts can be understood through some simple physical experiments.

Because it is from the river to the sea, the density of the liquid becomes larger, and according to the buoyancy formula, the buoyancy becomes larger.

It does not change, because when it is suspended, F floats = g, and G does not change, and F floats does not change.

Buoyancy remains the same. f float = g boat (in equilibrium by equilibrium force).

It's just that the V platoon has changed and will float up.

Although the amount of water discharged increases, the density of the river water is less than that of the seawater, the displacement increases, the density decreases, and the buoyancy remains unchanged (as long as the boat floats on the water, the buoyancy is equal to the gravity of the boat, and the buoyancy remains the same) pass: the river water density is 1g cm The density of seawater.

Unchanged because the ship floats, according to the balance of two forces g = f float, sea water.

A steamer made of steel plates can float on the surface of the water because it is made hollow, which increases the volume of water and increases buoyancy.

It is because the ship sails from the Yangtze River into the sea, and the buoyancy is unchanged. Because the steamer sails from the Yangtze River into the sea, the state is always floating, so the gravity and buoyancy are equal, the weight of the ship remains the same, and the buoyancy remains the same. Since seawater is denser than freshwater, the volume of discharged water decreases, so the hull rises.

The teacher didn't make it clear.

Indeed, your ship is not unloaded or loaded, and the buoyancy on the ship is just as great.

In fact, in order to increase stability, more ballast water will be filled into the lower part of the bow, that is, the nose part of the ship, so the height of the bow will be reduced, and at this time, the buoyancy of the sea water on the whole ship increases (increasing the buoyancy that needs to balance the weight of part of the ballast water).

This makes sense, but it's hard to think of without knowledge of navigation and ship construction.

If the gravitational force of the ship as a whole does not change and is in a state of floating equilibrium, it is the same size. It's just that the volume of water discharged may not be the same, because the density of water in the Yangtze River and the sea may not be the same. Usually the density of seawater is greater.

Because the boat is floating, so the G boat = F floating, then the boat is in the Yangtze River, and the buoyancy of the sea should be the same - correct.

You f is equal to g, the ship's weight remains unchanged, and then the density of the Yangtze River is small, so its displacement volume is large (f is equal to g, g is unchanged, the density decreases and the buoyancy increases, although it is redundant). Therefore, it is correct and purely handwritten.

Believe in yourself, the teacher is two, and the same is the same.

The boat sails from the sea to the river, the boat is always in a floating state, and the change in the density of the sea water and the river water will not affect the buoyancy of the floating object, and the buoyancy is always equal to the gravity of the boat. The change in density results in a change in the volume of the liquid discharged.

Only when suspending and sinking, the change of the density of the liquid will affect the change of buoyancy.

In suspension and floating, the volume of the discharged liquid is constant, so the buoyancy changes.

The density has become smaller, so do you know how the V row changes? Your teacher is talking about an object that is completely immersed in water, and in this case, V row = V object. However a ship you submerge in the water???

Float up somewhat. Because it is generally customary to regard the density of the river as 1, the density of the sea water is greater than 1, and the buoyancy of the ship in the sea water is greater than the buoyancy in the river water, so the ship will float a little.

Floating, the density of sea water is greater than that of fresh water.

The buoyancy remains unchanged, and the gravitational buoyancy is balanced when floating; Float up a little, because buoyancy = density · volume of water discharged·g, the density becomes larger, and the buoyancy remains the same, so the V row becomes smaller and will float.