Physics buoyancy questions in the second year of junior high school help me analyze it

Conclusion: Get bigger.

Ideas: The first step; To be clear, the hook under the spring dynamometer is pulling less and less on the plastic block. Because the plastic block is experiencing more and more buoyancy, the spring dynamometer above is reading smaller and smaller.

The second step is to look at the beaker, the water, and the plastic block as a whole. Now it is known that the tensile force of the plastic block is getting smaller and smaller, that is, the tensile force of the "cup, water, and plastic block" as a whole is getting smaller and smaller, so the pressure on the pallet balance tray becomes larger, and the indicator becomes larger.

Get bigger. Archimedes' principle shows that buoyancy is related to the volume of liquid discharged by the object, and the object is slowly immersed, the V row will be larger, and the buoyancy will be greater The gravity of the water and the beaker will not change, but the plastic block will have a downward force on the water. So the indication increases.

There is a spring pull force in this process, and the indication of the scales is equal to the gravitational force of the cup and the water plus the buoyant force of the water on the wooden block. And the buoyancy gradually increases. So the indication increases.

The water has a buoyant effect on the plastic block, and vertically upward, the plastic block will have a downward force on the water, because it is a balance force, so the change of the spring dynamometer has nothing to do with the change of the overall force.

Hehe, but the buoyancy will change, Archimedes' principle shows that buoyancy is related to the volume of liquid discharged by the object, the object is slowly immersed, the V row will be larger, and the buoyancy will be larger.

It makes sense.

f buoyancy = p liquid v row g, algebraically calculated, f bearing = f floating = f bearing - f self-weight = can be carried again.

It can carry 28 people, but it does not necessarily carry 28 people, and each person weighs 500n and chooses C

Multiplying 10 4-10000=14000 can exclude that the gravity of D person is about 50 a, and b is too absolute, so choose c

194. Geological team members prospect in high mountains and deep valleys, and use a portable instrument called buoyancy scale to accurately measure the density of ore The figure on the right is a schematic diagram of the buoyancy scale, the middle of it is a sealed hollow cylinder, a small basket is hung at the lower end of the cylinder, there is a hollow cylinder engraved with a seal at the upper end of the cylinder, and the lower end of the cylinder is equipped with a small disk, because the cylinder is hollow, and the small basket hanging below is heavier, so the buoyancy scale can maintain an upright floating state in the water Now it is necessary to measure the density of an ore, and the geological team members carry out the following operations:

a) Put the buoyancy scale into the water first, add weights in the small plate, so that the buoyancy scale sinks to the mark line and the water surface level, and write down the weight m1=125g in the plate

b) Remove all the weights in the plate, change the ore to be measured in the plate, then the mark line is above the water surface, and then add weights in the plate, so that the buoyancy scale sinks back to the mark line and the water surface level, and note the weight m2=25g in the plate

c) Remove all the weights in the plate, put the ore to be measured in a small basket, and then put the weights again in the plate, so that the buoyancy scale sinks to the mark line and the water surface level again, and notes the weight m3=45g in the plate

Q: (1) What is the mass of the ore? (2) What is the density of the ore?

How do you make a stone float on the water?

Velocity!

There is an object that puts it in the water, and when it is still there 3 5 out of the water, find its density

You do it yourself, and if you want the answer, you take it, and then you ask and I'll give you the answer.

I remember my teacher said that this kind of question cannot be found directly by density.

If the volume of the block is xcm3, according to the object floating on the water: the gravitational force of the object = the buoyancy of the object = the volume of liquid discharged:

Wood block gravity = buoyancy force on the wood block = Liquid gravity: 4 5xcm3 1g cm3 = 4 5xg (the volume of water discharged when in water The density of water).

Density of the latter liquid: 4 5xg 2 3xcm3 = gravity of discharging liquid volume of discharging liquid).

Block volume: 2 3cm3 (1 1 3) = xcm3 (discharging liquid volume Discharging liquid volume is the fraction of the volume of wood block immersed in water).

Block density: 4 5xg xcm3 = block gravity block volume).

The text description can be replaced with the corresponding physical symbol].

density of wood blocks plutonium; pwood*v=pwater*4 5v; p. wood =

the density of the latter liquid; p liquid*3 4v=pwood*v; P liquid =

P wood = (4 5) p water.

p latter liquid = (6 5) p water.