Question

The inner diameter of a cylindrical wooden pipe is 24 cm and its outer diameter is 28 cm. The length of the pipe is 35 cm. Find the mass of the pipe, if 1 cm³ of wood has a mass of 0.6 g.

Answer 1

Inner radius of the wooden pipe, r = $\frac{24}{2}$ = 12 cm

Outer radius of the wooden pipe, R = $\frac{28}{2}$ = 14 cm

Length of the wooden pipe, h = 35 cm

∴ Volume of wood in the pipe = $\mathrm{\pi }\left(R^2\mathit{-}{r}^{\mathit{2}}\right)h=\frac{22}{7}\times \left({14}^2-{12}^2\right)\times 35=5720{\mathrm{cm}}^3$

It is given that 1 cm³ of wood has a mass of 0.6 g.

∴ Mass of the pipe = Volume of wood in the pipe × 0.6 = 5720 × 0.6 = 3432 g = $\frac{3432}{1000}$ = 3.432 kg

Thus, the mass of the pipe is 3.432 kg.