Question

An iron pillar consists of a cylindrical portion 2.8 m high and 20 cm in diameter and a cone 42 cm high is surmounting it. Find the weight of the pillar, given that 1 cubic cm of iron weighs 7.5 gm.

Answer 1

⭐《ANSWER》

↪Actually welcome to the concept of the SURFACE AREAS AND VOLUME

↪Basically here it is the case of the Surmmouting of one shape on another

↪So in this type of cases , the diameter or the base dimension of the top shape is same to that of the below placed shape

↪Since here , the iron is used to make the piller of a Cylindrical and a conic section,

↪thus here we have to find the cost by Calculating amount of Volume required to make and weight of the pillar

↪Since

↪weight = unit measure × Volume

↪So after solving the weight is about

〽W = 692,370 grams

Answer 2

Step-by-step explanation:

Volume of cone=

3

1

πr

1

2

h

1

=

3

1

π(

2

r

)

2

×

2

h

=

3

1

π(

2

10

)

2

×

2

h

=

6

25πh

cm

3

Volume of frustum ABCD=

3

1

πh

2

(R

2

+r

2

+Rr)

=

3

1

π×

2

h

(10

2

+5

2

+10×5)

=

6

175πh

Required ratio=

6

175πh

6

25πh

=

175

25

=

7

1

=1:7