Question

A piece of metal pipe is 77 cm long ,the inside diameter of a cross-section is 4 cm.if the metal weight 8 gm per cubic metre.what is the weight of the piece of the pipe.

Answer 1

Answer:

The weight of the piece of pipe 2.05 kg.

Step-by-step explanation:

Given :

Height of metal pipe - 77 cm.

Now, we know that Radius is the half of diameter. So,

Inner radius of metal pipe, r = $\bf \dfrac{4}{2}\;cm\;=\;2\;cm$

Outer radius of metal pipe, R = $\bf \dfrac{4.5}{2}\;cm\;=\;2.25 cm$

Weight per cubic cm - 8 g.

To Find :

The weight of the piece of pipe.

Solution :

We know that :

$\bigstar\;\boxed{\textbf{Volume of the pipe} \bf= \pi R^2h - \pi r^2h}}$

So,

⇒ πh(R + r)(R - r)

⇒ $\dfrac{22}{7}$ × 77 × (2.25-2) (2.25+2)

∴ Volume of the pipe = 257.02 cm³

Now,

Weight of 257.02 cubic cm = 257.02 × 8 g.

So,

⇒ 2056.16 g

⇒ 2.05 kg.

∴ The weight of the piece of pipe 2.05 kg.

Answer 2

Answer:

The answer = 2.05 kg

Step-by-step explanation:

Solution :

★ We used the formula -

Volume of the pipe = πR²h - πr²h

Putting all the values, we get

==> Volume of the pipe = πR²h - πr²h

==> Volume of the pipe = πh(R+r)(R-r)

==> Volume of the pipe = 22/7 × 77 × (2.25-2) (2.25+2)

==> Volume of the pipe = 257.02 cm³

★ Weight of 257.02 cubic cm =

==> 257.02 x 8 g

==> 2056.16 g

==> 2.05 kg

$\therefore$ The answer = 2.05 kg