Question

A roller of diameter $0.9m$. and length $1.8m$ is used to press the ground. Find the area of the ground pressed by it, in $500$ revolutions.(Take $\pi =3.14$)

Answer 1

Given,

Diameter of roller $d=0.9m$

Length $\ell =1.8m$
$r=\frac{d}{2}=0.45$
To find area it rolled in $1$ revolution we have to find curved surface area.
Curved surface area:

$=2\pi r\ell =2\times 3.14\times 0.45\times 1.8=5.0868m^2$
Area covered in $500$ revolutions

$=500\times 5.0868=2543.4m^2$