2021 · Q75
A solid rod consists of a cylinder of height 20 cm and radius 7 cm. It is surmounted by another solid cylinder of height 10 cm and radius 3.5 cm. If 1 cubic metre of rod weighs 10000 kg, what is the mass of the rod ? (take π = 22/7)
Elementary MathematicsMensuration
- A34.65 kg
- B31.56 kg
- C3.465 kg
- D3.156 kg
Explanation
Volume = π·7²·20 + π·3.5²·10 = π(980 + 122.5) = 1102.5π = 3465 cm³ = 3.465 × 10⁻³ m³. Mass = 3.465 × 10⁻³ × 10000 = 34.65 kg. This is option (a).