Find the mass of a cylindrical iron pipe 2.1m long and 12cm in external diameter, if the metal is 1cm thick and of density 7.8g/cm cube. Take π=22/7

Answer 1

impatient much?
the volume of a cylinder is base area * length
you have a circular base, but with a hole in it. Such a ring of inner radius r and outer radius R has area
a = π(R^2-r^2)
So, your pipe has an outer radius R=6cm and an inner radius r=5cm
That makes the volume of metal
π(6^2-5^2) * 210 cm^3
and, as you know, mass = density * volume
= 7.8 * π(6^2-5^2) * 210 = _______ grams

Answer 2

I don't get were is my answers to my question

Answer 3

How did u get 210cm^3

Answer 4

Where is my answer