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

Answer:

693 kg

Step-by-step explanation:

We have,

Height of cylinder = 2.8 m = 280 cm.

Height of cone = 42 cm.

Diameter of cone = 20 cm.

Then, radius = 10 cm.

(i)

Volume of cone = (1/3) πr²h

                           = (1/3) * (22/7) * (10)² * 42

                           = 4400 cm³

(ii)

Volume of cylinder = πr²h

                                = (22/7) * (10)² * 280

                                = 88000 cm³

Now,

Volume of the pillar = Volume of cone + Volume of cylinder

                                 = 88000 + 4400

                                 = 92400 cm³

Cost per cm³ = 7.5 g

∴ Weight of pillar = (92400 * 7.5)/1000

                        = 693 kg.

Hope it helps!