A hollow cylindrical iron pipe with external and internal radii 8cm and 6cm respectively and length 35cm is melted and recast into a solid wure of thickness 2.8cm find the length of wire

Answer: length of wire = 500cm

Step-by-step explanation:

We would determine the volume of material used in making the hollow cylindrical iron pipe by subtracting the volume of the inner pipe from the volume of the outer pipe.

The formula for determining the volume of a cylinder is expressed as

Volume = πr²h

Volume of inner pipe = π * 6² * 35 = 1260π

Volume of outer pipe = π * 8² * 35 = 2240π

Volume of material used in making the hollow cylindrical iron pipe is

2240π - 1260π = 980πcm³

The solid wire made is cylindrical and has a thickness of 2.8cm. This is the diameter. It means that the radius of the wire is 2.8/2 = 1.4cm

Volume of wire = 980πcm³

Applying the volume of cylinder formula, it becomes

980π = π * 1.4² * h

where h = length of wire

h = 980/1.4² = 500cm