Question

An iron pillar has some part in the form of a right circular
cylinder and remaining in the form of a right circular cone. The
radius of base of each of cone and cylinder is 8 cm. The
cylindrical part is 240 cm high and the conical part is 36 cm high.
Find the weight of the pillar, if one cubic cm of iron weighs 10g.

Answer 1

Answer:

Volume of the pillar = Volume of the cylindrical part + Volume of conical part

Volume of a Cylinder of Radius "R" and height "h" =πR

2

h

Volume of a cone =

3

1

πr

2

h where r is the radius of the base of the cone and h is the height.

Hence, Volume of the pillar =(

7

22

×8×8×240)+(

3

1

×

7

22

×8

2

×36)=50688cm

3

If one cu cm wieighs 7.8 grams, then 50688cm

3

weighs 50688×7.8=395366.4 grams or 395.37kg

Answer 2

Answer:

Volume of the pillar = Volume of the cylindrical part + Volume of conical part

Volume of a Cylinder of Radius "R" and height "h" =πR

2

h

Volume of a cone =

3

1

πr

2

h where r is the radius of the base of the cone and h is the height.

Hence, Volume of the pillar =(

7

22

×8×8×240)+(

3

1

×

7

22

×8

2

×36)=50688cm

3

If one cu cm wieighs 7.8 grams, then 50688cm

3

weighs 50688×7.8=395366.4 grams or 395.37kg