Question

An iron pillar consists of a cylindrical portion of 2.8 m. height and 20 cm. in diameter and a cone of 42 cm. height surmounting it. Find the weight of the pillar if 1cm3 of iron weighs 7.5 g.

Answer 1

Given that, height of cylinder(H) = 2.8m = 280 cm, diameter(d) is 20 cm and height of cone(h) is 42 cm.
⇒ radius(r)
⇒ vol. of pole = vol. of cylinder + vol. of cone

= 92400 cm3
If 1 cm3 of iron weighs 7.5 g.
⇒ the weight of the pillar = 92400 × 7.5
= 693,000 g
= 693 kg (∵ 1kg = 1000g)