The mass of a metal block is 386g and the volume is 20cm3. What is the density of this metal block kg / m3? Tonight's homework is due tomorrow~ Format: according to the known, ask, answer to write

The mass of a metal block is 386g and the volume is 20cm3. What is the density of this metal block kg / m3? Tonight's homework is due tomorrow~ Format: according to the known, ask, answer to write

It is known that M = 386g, v = 20cm ^ 3
Seeking density
P=m/V=386÷20=19.3g/cm^3=19.3×10^3kg/m^3
The density of metal is 19.3 × 10 ^ 3kg / m ^ 3

If there is a piece of metal with a mass of 237g and a volume of 30cm3, what is the density of the metal______ G / cm3______ If the metal is cut in half, the density of half of it is______ kg/m3．

The density of the metal ρ = MV = 237g30cm3 = 7.9g/cm3, which means that the mass of the metal is 7.9g for 1cm3; the density is the property of the material, which has nothing to do with the mass and volume of the material and does not change with the change of the mass and volume. If the metal is cut into two parts, the density of half of the metal is still 7.9g/cm3 = 7.9 × 103kg / m3

The spring scale is hung with solid metal, the metal is submerged in water, the spring scale shows 29.4n, the metal gravity and buoyancy, and the density is 7000kg / m3
It's better to have a simple idea

At the beginning, we set the basic physical quantity: let the volume of the solid metal block be v m ^ 3, then its mass is 70000 V kg, and its gravity is 70000 V Newton. When it is immersed in water, the buoyancy it receives is: F floating = ρ water × V × g = 1000 × V × 10 = 10000 V (Newton)
70000vn - 10000vn = 29.4n
According to the calculation, v = 0.00049, that is, the volume of metal block is 0.00049 cubic meter, the gravity is 70000 × 0.00049 = 34.3 (Newton), and the buoyancy is 4.9 Newton