Question

the inner radius of a hollow cylindrical pipe is 8cm and the thickness is 2.5 cm find the outer radius of the pipe

Answer 1

i think you're question is incorrect....

It should be-

A hollow cylindrical iron pipe is of length 28cm. Its outer and inner diameters are 8cm and 6cm respectively. Find the volume of the pipe and weight of the pipe if 1cu.cm of iron weighs 7gm. (Take π=722)

Let r,R and h be the inner, outer radii and height of the hollow cylindrical pipe respectively.

Given that 2r=6cm, 2R=8cm, h=28cm

Now, the volume of the pipe, V=π×h×(R+r)(R−r)

∴ Volume, V=616cu.cm

Weight of 1cu.cm of the metal =7gm

Weight of the 616cu.cm of metal =7×616gm

Thus, the weight of the pipe =4.312kg