Question

the inner diameter of a cylindrical wooden pipe is 24 cm and its outer diameter is 28cm . the lenght of the pipe is 35 cm.find the mass of the pipe if 1cm3 of wood has a mass of 0.6 g.

plz explain this in detail

and also tell how to solve such sums which have inner and outer diameters/radii nd CSA /TSA /VOLUME must be found. they r all so confusing...............

Answer 1

Here Inner radius (r) = 24/2 = 12cm

Outer radius (R) = 28/2 = 14 cm

h = length of pipe = 35 cm

Volume of the pipe = 

= πR²h - πr²h

= πh ( R² - r² )

= 22/7 * 35 * (142 - 122 )

= 22/7 * 35 * (14 - 12) (14 + 12)

= 22/7 * 35 * 2 * 26

= 5720cm3

Now, 1 cm³ wood = 0.6g

5720cm³ = (5720 * 0.6)g

= 3432.0 g

= 3.432 kg