Question

If a rod of 2 cm diameter and 30 cm length is connected with a wire of 3m length and diameter 1 cm. Then find the total surface area.​

Answer 1

Total Surface Area =  $\bold {506.78\ cm^2}$

Step-by-step explanation:

Given,Diameter of rod = 2 cm

   Radius of the rod = 1 cm

Length of the rod = 30 cm

Length of the wire =3 m = 300cm

Diameter of the wire = 1 cm

Radius of the wire = 0.5 cm

We know that Total Surface Area of the Cylinder = $2\pi r(r+h)$

Total Surface Area of the Rod =$2\pi r(r+h)$

                                                  = $2\times \frac{22}{7}\times 1\times(1+30)$

Total Surface Area of the wire = $2\pi r(r+h)$

                                                   =$2\times \frac{22}{7}\times 0.5(0.5+300)$

Total Surface Area = (Total Surface Area of the Rod + Total Surface Area of the wire) - Area of Base of wire

                                = [$2\times \frac{22}{7}\times 1\times(1+30)$ + $2\times \frac{22}{7}\times 0.5(0.5+300)$] - $\pi r^2$

                                =  [$2\times \frac{22}{7}\times 1\times(1+30)$ + $2\times \frac{22}{7}\times 0.5(0.5+300)$] - $\frac{22}{7}(0.5)^2$

                               = $\bold {506.78\ cm^2}$

Answer 2

Answer:

Step-by-step explanation:

Volume of the wire=Volume of the rod

⇒πr2(300)=π(2/2)^2(30)

$r^2=\frac{\pi (1)^2(30)}{\pi 300}$

$r^2=\frac{1}{10}$

$r=\sqrt{} \frac{1}{10}$

$r=\frac{1}{\sqrt{10} }$

$d=2r=\frac{2}{\sqrt{10} }$

$d=\frac{2\sqrt{10} }{10}$

$d=\frac{\sqrt{10} }{5} cm$