Question

A solid metallic sphere of diameter 21cm melted and recasted into a number of smaller cones,each of diameter 3.5 cm and height 3cm. Find the number of cones so formed.

Answer 1

Answer:Concept

The mass of metal will remain constant irrespective of the shape.

Solid metallic sphere is melted in to smaller number of cones.

Volume of sphere is

4/3 π r³= 4/3 π (21/2)³

Volume of one cone 1/3 π r²h

1/3 π (3.5/2)² 3

Vol of n cones= n x 1/3 π (3.5/2)² 3

M = v X d (density)

Mass of sphere =mass of cones

v x 4/3 π (21/2)³= v x n x 1/3 π (3.5/2)² 3

Solve answer should be 126

Note:

I have tried to explain full concept by taking mass and density. volume.

We can solve by only taking volume (as material is same and density will not change)