Question

Iron pipe is 21 m long and its exterior diameter is 8 cm if the thickness of the pipe is 1 cm and the iron weight is 8 centimetre cube find the weight of the pipe

Answer 1

Answer:

lenght=21m=21*100=2100cm which is height (* means multiplied)

exterior diameter=8cm

radius=d/2

=8/2

=4cm

let us take exteror radius as R

thickness=1cm

 iterior radius=exteriror(outer) radius-thickness

                    =4-1

                     =3cm(let inner radius be r

volume of pipe (which is hollow)=π(R squrae-r squrae)*height

                                                   =22/7(4 squrae-3 squrae)*2100

                                                    =22/7(16-9)*2100

                                                     =22/7*7*2100

                                                     =46200cubic cm

weight = 46200*8

           =369600gram

            =369.6kilogram