Question

A hollow spherical shell is made of a metal of density 4.5g per cm³. If its internal and external radii are 8cm and 9cm respectively, find the weight of the shell.

Answer 1

It is given that

Internal radius of the spherical shell = 8cm

External radius of the spherical shell = 9cm

Density of metal = 4.5g per cm³

We know that

Weight of shell = 4/3 π [R³ – r³] × Density

By substituting the values

Weight of shell = 4/3 × (22/7) × [9³ – 8³] × (4.5/1000)

On further calculation

Weight of shell = 4/3 × (22/7) × [729 – 512] × (4.5/1000)

So we get

Weight of shell = 4/3 × (22/7) × 217 × (4.5/1000)

We get

Weight of shell = 4.092kg

Therefore, the weight of the shell is 4.092kg.