Question

Find the weight of a lead pipe 35 cm long. The external diameter of the pipe is 2.4 cm and the thickness of the pipe is 2mm, given 1 cm³ of lead weighs 10 gm.

Answer 1

External radius 'R' = 1.2 cm
Internal radius 'r' = 1.0 cm      ...(Since internal radius = external radius - thickness)
Height 'h' = 35 cm

∴ Volume of the pipe = πh[ R² - r² ]
= `22/7` x 35 x [(1.2)² - (1.0)²]
= 48.4 cm³
∴ Weight of lead pie = 10 x 48.4 = 484 gm.