Physical density calculation questions in the second year of junior high school, physical density ca

Density = mass volume.

Gravity = mass.

Mass = gravity

Because half of the block is submerged in water, buoyancy = density of water x volume of water discharged.

The buoyancy experienced by the dynamometer reading is known =

Volume of drained water = buoyancy The density of the water.

The density of water is a known quantity, and the volume of water discharged is obtained.

The volume of drained water x2 is equal to the volume of the block.

At this point, the density of the block can be found.

In mercury, the density of the two is compared, and the density of the block is greater than the density of the mercury, that is, the sinking is reversed.

All immersed in kerosene according to the buoyancy formula f = kerosene density x block volume.

Then use the reading of the dynamometer.

I'm sorry I only told you the idea, and organize the specific formatting steps yourself, so that you can really learn it.

Ice with XDM melts.

Column. 30dm³-xdm³）+xdm³*

Solve x=2 so there is 2dm of ice that melts into water.

Quality: 2dm *

So some of the ice melts into water.

Summary. 1)89 30 "So this ball is hollow.

1)89 30 "So this ball is hollow.

2) 89 i.e. the volume of the hollow part is 20cm

3)(109-89) 20=20 20=1g cm According to the data in the table above, the substance injected into the hollow sphere is pure water.

Dear, the above is the detailed answer to the 3 questions in the question above, you see.

ρ=m/v

420g/500cm^3

Not up to standard: Too much water.

Suppose a milliliter of alcohol is added.

Then the mass of alcohol added is grams.

m/v (420g+

Solution a = 500ml

An additional 500ml of alcohol should be added.

An area in the upper reaches of the Yangtze River flows 25 million tons of soil into the river every year, which is equivalent to how many square meters of 40cm thick land is lost in the region every year? (The average density of the soil is.)

It stretches on the road around the island in Xiamen"Never Stop" group carving, the scene of the marathon will always be fixed on the most beautiful track in the world, the size of the sculpture is about the same as a real person, if its density is 8000kg cubic meters, the mass of each statue is about ().

a 5kg b50kg c500kg d5000kg

Application of density.

1 When a bottle is filled with oil, the total mass is, when it is filled with water, the total mass is, and the mass of the water is, find the density of the oil

2 The mass of object A is three times that of object B, so that the ratio of the volume of objects A and B is 3:2, and the ratio of the density of objects A and B is obtained

3 The mass of the vial is 210g after being filled with water, if a 45g metal block is placed in the bottle first, and then filled with water, the mass is weighed as 251g, and the density of the metal block is obtained

4 The densities of the two metals are respectively , and the two metals of the same mass are made into alloys, and the density of the alloy is proved to be (assuming that the volume is unchanged during the mixing process).

5 There is a handicraft with a nominal pure gold mass, its mass is 100g, and the volume is 6cm3, please use two methods to determine whether it is made of pure gold (which does not contain other common metals)? （

6 There are two liquids with a density of and can be fully mixed, and , if the two liquids with a volume of and are mixed respectively, and , and the total volume does not change after mixing, verify: the density of the mixed liquid is or

7. The density of liquid A is 40cm3 and the density of liquid B is 20cm3, and the volume after mixing becomes the original 90, and the density of the mixed liquid is found

Solution: (1) v water = m water p water =

V stone = 3x10-4m3 - 2x10*-4m3 = 1x10*-4m3 (2) The volume of each stone v=1x10*-4m3 25=4x10*-6m3

Stone density p=m v=

1) The volume of water is.

The total volume of the stone in the bottle = 3 * 10 -4 - 2 * 10 -4 = 10 -4m3

2) Density of stones =

(1) The cubic of ten.

It seems like that's it, maybe a little bit more

(1) v water = m water p water =

v stone = v total -v water =

2) P stone = m stone V stone =

（1）v1:v2

2）p1:p2

3）p2:p1

Just remember the formula: p=m v.

For example, the first question:

p1=m1/v1，p2=m2/v2

Because p1 = p2

So m1 v1 = m2 v2

So m1 m2=v1 v2

Volume of wood: v total - v core = (

The quality of the wood: M wood = P wood V wood = attention unit.

The quality of the lead core: M core = m total - m wood = about not to fall, note that you are wrong at this step, the front is not bring, the back is with , and you ignore this! ）≈

Volume of refill: V-core = (

Density: P core = M core V core =

543-300 = 243g mass of metal.

953-543=410g is the mass of water.

The density of water is.

The volume of water in which the metal is placed is 410 cm3

The volume of the previous cup was 800-300 = 500 cm3 Density of metal = mass of metal Volume of metal = 243 (500-410) =

By filling with water, the water quality can be 800-300 = 500g, according to p = m v, the bottle volume = (500 * 10 negative cubic power) divided by 1000 (the unit density of water), volume = (negative cubic meter) cubic meter, according to the second time, it can be seen that the metal mass = 543-300 = 243g, the second water mass is (953-543) = 410g, and then by the density calculation formula deformation can obtain v water = (410 * 10 negative cubic power) divided by 1000, v water = (negative cubic) cubic meter, so volume of metal = bottle volume - v water = negative cubic, p metal = mass of metal divided by volume of metal = 2700 kg per cubic meter.

The mass of water in the three = the total mass of the three - the total mass of the bottle and the metal particles = 953 - 543 = 410g

So the volume of the metal = 500 - 410 = 90 cubic centimeters.

p=m/vp=243/90=

This problem is solved using the volume equality method.

The volume of the bottle can be obtained according to the title.

v = v water = m water water = (800-300) = 500 cm3

Fill the empty bottle with some metal pellets and fill it with water at this time.

V metal = V bottle - V water (back) = 500 - (953-543) = 90 cm3

m metal = 543-300g = 243g

Metal = m metal v metal = 243g 90cm3 = so the metal may be aluminum.

V bottle = V water = m water Water = (800-300) = 500cm3