Question

A pice of metal pipe is 77 cm , long the inside diameter of a cross section is 4 cm . if the metal weight 8 gm per cu cm. what is the weight of the pices of pipe ?

Answer 1

Given the inner diameter  as 4 cm, outer diameter 4.4 cm , length of pipe is 77 cm
Inner curved surface area  = 2πrh
where r is the inner radius, h is the height of the cylinder
inner radius =( inner diameter) /2
= 4/2 
= 2 cm
Inner curved surface area  = 2πrh
= 2*π*2*77
=2*(22/7)*2*77
= 968 cm2