Question

A wheel of perimeter $220$ $cm$ rolls on a levelled road at a speed of $9$ $km/hr$. How many revolution does the wheel makes per second?

Answer 1

$v=9$ $km/hr=(\frac{5}{18}\times 9)$ $m/s=\frac{5}{2}$ $m/s$
And, $2\pi r=-220$
$r=35$ $cm$
$v=\omega R\to \frac{5}{2}=\omega \times \frac{35}{100}$
$\omega =\frac{100}{14}=7.14$ $rad/s$
One revolution $=2\pi$ $rad=6.28$
$\therefore$ No. of revolution per second $=\frac{\omega }{2\pi }=1.13$