Question

a pipe made of metal 1cm thick , has and external radius of 11cm. find the volume of metal used in making 2.4 m long pipe​

Answer 1

The volume of metal used in making 2.4 m long pipe is 1.58 cm³

Explanation:

From the question,

The external radius is 11cm.

Also, the thickness of the pipe is 1cm, then we can determine the internal radius.

Internal radius = External radius - the thickness

Internal radius = 11cm - 1cm

Internal radius = 10cm

Now, to find the volume of metal used in making the long pipe,

The volume of metal used in making the long pipe is the difference between the volume of the external cylinder and the volume of the internal cylinder.

Volume of a cylinder is given by the formula below

`V = \pi r^(2)h`

Where
`V` is the volume of the cylinder

`\pi` is constant ( Take
`\pi` = 3.14)

`r` is the radius

and
`h` is the height

Let the radius of the external cylinder be R,

then, R = 11 cm = 0.11 m

and let the radius of the internal cylinder be r

then, r = 10 cm = 0.10 m

Then,

The volume of metal used in making the long pipe =
`\pi R^(2)h - \pi r^(2)h`

=
`\pi (R^(2) - r^(2))h`

=
`3.14*(0.11^(2) - 0.10^(2))*2.4`

=
`3.14*(0.0121 - 0.01)*2.4\\`

=
`3.14*(0.0021 )*2.4\\`

= 0.0158 m³ or 1.58 cm³

Hence, the volume of metal used in making 2.4 m long pipe is 1.58 cm³