Hollow iron pipes are made in lengths of 5 metres. The external diameter of the pipes is 30mm,

Question

while the internal diameter is 20mm.?

Determine the volume of iron in each length of pipe give answer in m^3. 

The density of iron in kgm^3

Answer 1

The External diameter of the hollow iron pipe is 30 mm.

External Radius of the hollow iron pipe is 30 / 2 = 15 mm = 0.015

The Internal diameter of the hollow iron pipe is 20 mm.

Internal Radius of the hollow iron pipe is 20 / 2 = 10 mm = 0.010

Length of the pipe is 5 mts.

Volume of the External iron pipe = πr² * l.

Volume of the External iron pipe = π * (0.015)² * 5

Volume of the External iron pipe = 3.53 * 10^-3 m³

Volume of the Internal iron pipe = πr² * l.

Volume of the Internal iron pipe = π * (0.01)² * 5

Volume of the Internal iron pipe = 1.57 * 10^-3 m³

Therefore volume of the hollow iron pipe = External Volume - Internal Volume

Volume of the hollow iron pipe = 3.53 * 10^-3 - 1.57 * 10^-3

volume of the hollow iron pipe = 1.96 * 10^-3 m

Therefore the volume of the hollow iron pipe is 1.96 * 10^-3 m.

Answer 2

(b)

The External diameter of the hollow iron pipe is 30 mm.

External Radius of the hollow iron pipe is 30 / 2 = 15 mm = 0.015

The Internal diameter of the hollow iron pipe is 20 mm.

Internal Radius of the hollow iron pipe is 20 / 2 = 10 mm = 0.010

Length of the pipe is 5 mts.

Mass of the hollow pipe = 15.4 kg.

Volume of the External iron pipe = πr² * l.

Volume of the External iron pipe = π * (0.015)² * 5

Volume of the External iron pipe = 3.53 * 10^-3 m³

Volume of the Internal iron pipe = πr² * l.

Volume of the Internal iron pipe = π * (0.01)² * 5

Volume of the Internal iron pipe = 1.57 * 10^-3 m³

Therefore volume of the hollow iron pipe = External Volume - Internal Volume

Volume of the hollow iron pipe = 3.53 * 10^-3 - 1.57 * 10^-3

volume of the hollow iron pipe = 1.96 * 10^-3 m³

Density = Mass / Volume

Density = 15.4 kg / (1.96 * 10^-3)

Density = 7857.14 kg/m³.

Therefore the density of the iron is 7857.14 kg/m³.