What is the mass of a birch board 400 cm long, 15 cm wide and 2 cm high? The density of a birch tree is 650 kg / m3.

Initial data: a (length of a birch board) = 400 cm; b (width of a birch board) = 15 cm; h (birch board height) = 2 cm.

Reference values: ρ (density of birch tree) = 650 kg / m ^ 3.

SI system: a = 400 cm = 4 m; b = 15 cm = 0.15 m; h = 2 cm = 0.02 m.

We calculate the mass of a birch board by the formula: m = ρ * V = ρ * a * b * h.

Let’s perform the calculation: m = 650 * 4 * 0.15 * 0.02 = 7.8 kg.

Answer: The mass of a birch board is 7.8 kg.