A bar weighing 300 grams has a size of 15x5x2 cm. Determine the density of the substance. How to solve?

m = 300 g = 0.3 kg.

a = 15 cm = 0.15 m.

b = 5 cm = 0.05 m.

c = 2 cm = 0.02 m.

ρ -?

The density of a substance ρ is a scalar physical quantity equal to the ratio of the mass of a substance m to the volume V it occupies: ρ = m / V.

Since the bar has the shape of a rectangular parallelepiped, its volume V is expressed by the product of its three parameters: length a, width b, height c: V = a * b * c.

The formula for the density of the substance from which the bar is made will take the form: ρ = m / a * b * c.

ρ = 0.3 kg / 0.15 m * 0.05 m * 0.02 m = 2000 kg / m3.

Answer: the bar is made of a substance with a density of ρ = 2000 kg / m3.