Question

An iron pole consisting of a cylindrical portion 110 cm high and of base diameter 12 cm is surmounted by a cone 9 cm high. Find the mass of the pole, given that 1 cm³ of iron has 8 gm of mass (approx). (Take π = `355/113`)

Answer 1

 

Radius of the base of poles (r) = 6 cm

Height of the cylindrical part (h₁) = 110 cm

Height of the conical part (h₂) = 9 cm  

Total volume of the iron pole

= `pir^2h_1 + 1/3pir^2h_2`

= `pir^2(h_1 + 1/3h_2)` 

= `355/113 xx 6 xx 6(110 + 1/3xx9)` 

= `355/113 xx 36 xx 113` 

= 12780 cm³ 

Weight of 1 cm³ = 8 gm 

Therefore, total weight = 12780 × 8

= 102240 gm

= 102.240 kg  ...`[∵ 1 gm = 1/1000 kg]`

= 102.24 kg