What material is a rectangular bar 1 cm. × 20 mm. × 1 dm. Made of, if its mass = 0.178.

To find out the type of material from which the presented rectangular bar was made, we use the formula: ρb = m / V = m / (l * b * s), where m is the mass of the presented bar (m = 0.178 kg); l is the length of the presented bar (l = 1 dm, in the SI system l = 0.1 m); b is the width of the bar (b = 20 mm, in the SI system b = 0.02 m); s – thickness (s = 1 cm, in SI s = 0.01 m).

Let’s perform the calculation: ρb = m / (l * b * s) = 0.178 / (0.1 * 0.02 * 0.01) = 8900 kg / m3 (corresponds to the density of copper (bronze)).

Answer: The presented rectangular bar should have been made of copper (bronze).