# Two bars of the same mass have dimensions 2x2x2 cm and 3 х3 х1 cm. What is the density of the substance

**Two bars of the same mass have dimensions 2x2x2 cm and 3 х3 х1 cm. What is the density of the substance from which the second bar is made, if the first is made of tin?**

Body mass:

m = ρ * V, where m is the desired mass kg), ρ is the density of the body (kg / m ^ 3), V is the volume of the body (m ^ 3).

First bar weight:

m1 = ρ1 * V1, where ρ1 (tin) = 7310 kg / m ^ 3, V1 = 2 * 2 * 2 cm ^ 3 = 8 cm ^ 3 = 8 * 10 ^ -6 m ^ 3.

Second block weight:

m2 = ρ2 * V2, where V2 = 3 * 3 * 1 cm ^ 3 = 9 cm ^ 3 = 9 * 10 ^ -6 m ^ 3.

Since m1 = m2, then

ρ1 * V1 = ρ2 * V2.

ρ2 = ρ1 * V1 / V2 = 7310 * (8 * 10 ^ -6) / (9 * 10 ^ -6) ≈ 6500 kg / m ^ 3.

According to the table of the density of substances, we determine that the second bar is made of zirconium.

Answer: The second bar is made of zirconium.