On the conversion of mathematical units, such as (1kg = 1000g)

Length unit conversion 1 km = 1000 m 1 m = 10 decimeter 1 decimeter = 10 cm 1 m = 100 cm 1 cm = 10 mm area unit conversion 1 square kilometer = 100 ha 1 ha = 10000 M2 1 square meter = 100 square decimeter 1 square decimeter = 100 square centimeter 1 square centimeter = 100 square millimeter volume unit conversion 1 cubic meter = 1000 cubic decimeter 1 cubic decimeter = 1000 cubic centimeter 1 cubic decimeter = 1 liter, 1 cubic centimeter = 1 milliliter, 1 cubic meter = 1000 liter, 1 ton = 1000 kilogram, 1 kilogram = 1000 gram, 1 kilogram = 1 kilogram, 1 yuan = 10 Jiao, 1 jiao = 10 minutes, 1 yuan = 100 minutes, 1 century = 100 years, 1 year = December, 31 days, 1 / 3 / 5 / 7 / 8 / 10 / 12, 30 days, 4 / 6 / 9 / 11, February 28, February 29, and 365 days in leap year, In a leap year, there are 366 days, 1 day, 24 hours, 1 hour, 60 minutes, 1 minute, 60 seconds, 1 hour, 3600 seconds in the whole year. The commonly used graphic calculation formulas in primary school mathematics are as follows: 1. Square C perimeter s area a side perimeter = side length × 4 area = side length × side length C = 4A s = a × a s = A2 2, cube V volume a side surface area = side length × side length × 6, volume = side length × side length × side length s surface = a × a × 6, table = 6A2, v = a × a v = A3 3, Rectangle C perimeter s area a side perimeter = (length + width) × 2 C = 2 (a + b) area = length × width s = AB 4, cuboid V volume s area a length B width h height (1) surface area = (length × width + length × height + width × height) × 2 (2) volume = length × width × height s = 2 (AB + ah + BH) v = ABH 5, triangle s area a bottom h area = bottom × height △ 2 s = ah △ 2, triangle height = area × 2 △ bottom triangle = area × 2 △ height 6, parallelogram S area a bottom h height area = bottom × height s = ah 7, trapezoidal s area a upper bottom B lower bottom h height area = (upper bottom + lower bottom) × height ／ 2 s = (a + b) × h ／ 28, circular s area C circumference π circumference D diameter R radius circumference = diameter × π circumference = 2 × π × radius area = radius × π C = π D C = 2 π r s = π R 2 D = C ／π d = 2R r = D ／ 2 r = C ／ 2 π s ring = π (r2-r2) 9, Cylinder V volume h height s bottom area R bottom radius C bottom perimeter side area = bottom perimeter × height (2) surface area = side area + bottom area × 2 (3) volume = bottom area × height s side = ch s side = π DH v = sh v = π r2h cylinder volume = side area △ 2 × radius 10 cone V volume h height s bottom area R bottom radius volume = bottom area × height △ 3 V = sh △ 3

Physics problems about density
Put the same two balls into liquid a and liquid B respectively. When the two balls are stationary, the liquid level of the two liquids is the same, the small balls in liquid a are suspended, and the small balls in liquid B are floating. Then the pressure of liquid a and liquid B on the bottom of the container is (both containers are cuboids)
A is greater than B
B A is less than B
C a equals B
D all the above situations are possible
My answer is not the same as the reference answer. I chose B, but the answer is C. I'm confused,

The answer is C
The two balls are still in the water, which means that their buoyancy is equal to gravity. Because the gravity of the two balls is equal, they are equally buoyant``
So if the masses of the liquid are equal, then their pressures are equal
The ball in a floats and the ball in B floats, which indicates that the volume of liquid discharged by a is larger and the density of the named a is smaller
You can use Newton's system of particles```
The vertical acceleration of a and B is 0`
Then the gravity of the container plus the pressure of the liquid equals the support of the table
And the supporting force of the table is equal to the total weight of the liquid plus the weight of the ball. If the total weight of the liquid is equal, then the current pressure is equal````
Believe me, it's just not clear```

1. When a bottle is filled with water, the total mass of water and bottle is 120g; when it is filled with alcohol, the total mass of alcohol and bottle is 100g (the density of alcohol is ρ = 0.8 * 10 ^ 3 kg / m ^ 3). What is the mass of alcohol in the bottle?
2. The mass of a mannequin is 60kg. In order to make a plaster statue of the same size, how big is its volume?
3. A roll of aluminum wire, question: how to calculate the length of this roll of aluminum wire without ruler?

M water + m bottle = 120 ------ (1) m wine + m bottle = 100 ------ (2) the volume is the same, so v = m water / P water = m wine / P wine. Because P water / P wine = 1 / 0.8 = 5 / 4, so m water / M wine = 5 / 4 is substituted into (1) formula to get m wine = 80g 3, a roll of aluminum wire

Density in Physics
A bottle with a volume of 0.0003m contains 0.2kg of water. A thirsty crow puts a small stone with a mass of 0.01kg into the bottle each time. When the crow throws 25 identical stones, the water rises to the bottle mouth. The total volume and density of stones in the bottle are calculated

It is known that the volume of the bottle is 3 * 10 cubic meters to the negative fourth power, the mass of water in the bottle is 0.2kg, the mass of small stones is 0.01kg, and the number of stones is n = 25

Physical test procedure and density formula
There is no measuring cylinder, only an empty bottle, a balance (including weights), enough water, please find a way to use these equipment to measure the density of edible oil
Requirements: (1) write the steps (2) write the formula for calculating the density of edible oil (write the process)

Fill the empty bottle with water
2. Measure its mass M1 with a balance and record the data
3. Take out the water and dry the bottle
4. Fill the bottle with cooking oil
5. Measure its mass M2 with balance and record the data
P edible oil = (m2 / M1) g / cm ^ 3

On mass and density in Physics
17. The mass of a copper ball is 5.16kg, and the volume is 6 × 10 - 4m3

17. The density of copper is: ρ = 8.9 × 103kg / m3; the volume of copper with mass of M = 5.16kg is: v = m / ρ = 5.16kg / (8.9 × 103kg / m3) = 5.798 × 10-4 m3 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; ∫ V < V ball = 6 × 10-4 m3 & nbsp

"Density is directly proportional to mass and inversely proportional to volume", right? Why?

No, density is an attribute of matter. It doesn't change with the mass or the volume. M = ρ V is just a formula for calculating the mass, not a definition of density. Density is a physical quantity reflecting the characteristics of matter. The characteristics of matter refer to the properties that matter itself has and can distinguish from each other

Comparison of mass and density
An iron ball has a volume of 2 and a mass of 15.6 kg. Is it hollow or solid? If it is hollow, what is the volume of the hollow? If the hollow part is filled with lead, what is the total mass of the ball? (the density of iron is 11.3 * 10.3 kg / m3)
The second question is: the mass of a hollow copper ball with a volume of 30 cm3 is 178 grams. When the hollow part of the ball is filled with some liquid, the total mass of the ball is 314 Grams. What is the liquid material injected?

An iron ball has a volume of 2.5 decim3 and a mass of 15.6 kg. Is it hollow or solid? If it is hollow, what is the volume of the hollow? If the hollow part is filled with lead, what is the total mass of the ball? (the density of iron is 11.3 * 10.3 kg / M3). If it is solid, its mass should be: M = 2.5 * 11.3 = 28.25

The mass of a 8.0 × 10 - m steel ball is 25kg. Is it solid or hollow?
The mass of a steel ball with a volume of 8.0 × 10 ~ (- 179; m ~ (- 179;) is 25kg. Is it solid or hollow? Why? (ρ steel = 7.8 × 10 ~ (- 179; kg / M ~ (- 179;)] [detailed process: known... Ask. 90 ° bow = =

Density = mass / volume
The density of the steel ball = 25 / (8.0 × 10 - (?) 179;) = 3125

0.8×10^3kg/m³=? kg/dm³=?g/m³=?g/dm³

0.8×10^3kg/m³=0.8 kg/dm³=800000g/m³=800g/dm³
The third one I doubt you is / cm
0.8×10^3kg/m³=0.8 kg/dm³=8g/cm³=800g/dm³

On the conversion of mathematical units, such as (1kg = 1000g)