Question

A cylindrical road roller made of iron is 1 m long, Its internal diameter is 54 cm and the thickness of the iron sheet used in making the roller is 9 cm. Find the mass of the roller, if 1 cm³ of iron has 7.8 gm mass. (Use π = 3.14)

Answer 1

We have to find the mass of the roller.

Radius of inner cylinder(r₁) = 27 cm

Radius of outer cylinder

(r₂) = (27 + 9) cm

= 36 cm

Length of the cylinder(h) = 100 cm

So, volume of iron,

`=rh(r_2^2-r_1^2)`

=(3.14)(100)(1296-729)

=178038 cm³

It is given that, 1 cm³ of iron has a mass of 7.8 gm.

So the mass of iron used,

= (178038)(7.8) gm

= 1388696.4 gm

= 1388.7 kg