Question

the external diameter of a cylindrical iron pipe 25 dm long is 14 cm the thickness of iron is 1.75 cm. find the weight of the pipe if 1 CU cm of iron weight 10g

Answer 1

Answer:

216.5625 kg

Step-by-step explanation:

Find the external radius:

External Diameter = 14 cm (Given)

External Radius = 14 ÷ 2 = 7 cm

Find the internal radius:

Thickness of the iron = 1.75 cm

Internal Radius = 7 + 1.75 = 8.75 cm

Find the volume of the iron:

Length = 25dm = 250 cm

Volume = π(r1)²(h) - π(r2)²(h)

Volume = π(8.75)²(250) - π(7)²(250) = 21656.25 cm³

Find the weight:

1 cm³ = 10g

21656.25 cm³ = 21656.25 x 10 = 216562.5 g

216562.5 g = 216.5625 kg

Answer: 216.5625 kg

Answer 2

Answer:

216365.625 g

Step-by-step explanation:

As given in the Question

External diameter = 14 cm

Thickness = 1.75 cm

Length = 25 dm = 25 * 10 cm = 250 cm                     ∴ (1 dm = 10 cm)

1 cm³ = 10 g

To find is the Weight of the pipe

External diameter = 14 cm

External radius =r₁ = $\frac{External Diameter}{2}$

                           =$\frac{14}{2}$

                           = 7 cm

Thickness = 1.75 cm

Internal radius =r₂= External Radius + Thickness

                        =7 + 1.75

                        = 8.75 cm

Now we Know that For cylindrical pipe

Volume = π(r₂)²(h) - π(r₁)²(h)                   ∴ (π=3.14)

Putting the values in the equation

Volume = (3.14)*(8.75)²*(250) - (3.14)*(7)²*(250)

Volume = 60101.5625 - 38465

Volume = 21636.5625 cm³

Now it is given that

1 cm³ = 10 g

so

21636.5625 cm³ = 21636.5625 * 10 g

                            =216365.625 g

So the weight of the iron is 216365.625 g