Question

Question 7
A cylinderical roller 2.5 m in length, 1.75 m in radius when rolled on a road was found to cover the area of $5500m^2$. How many revolutions did it make?

Answer 1

Given, length of the cylindrical roller, h = 2.5 m
Radius of the cylindrical roller, r = 1.75 m
Total area rolled on a road by cylindrical roller $=5500m^2$
$\therefore$ Area rolled in one revolution = Curved surface area of the cylindrical roller
$=2\pi rh=2\times \frac{22}{7}\times 1.75\times 2.5$
$=\frac{44\times 4.375}{7}=\frac{192.5}{7}=27.5m^2$
$\therefore$ Number of revolutions rolled by a cylindrical roller
$=\frac{\text{Total area rolled by cylindrical roller}}{\text{Area rolled in one revolution}}=\frac{5500}{27.5}=200$