Question

Find the distance covered by the wheel of a car in 500 revolutions if the diameter of the wheel is 77 cm.

Answer 1

Radius of the wheel =$\frac{\mathrm{Diameter}\mathrm{of}\mathrm{the}\mathrm{wheel}}{2}$
$\Rightarrow \mathrm{r}=\frac{77}{2}\mathrm{cm}$
Circumference of the wheel =$2\pi r$
$$\begin{gathered} =(2\times \frac{22}{7}\times \frac{77}{2}) \\ =242\mathrm{cm} \end{gathered}$$

In 1 revolution the wheel covers a distance equal to its circumference.

$$\begin{gathered} \therefore \mathrm{Distance}\mathrm{covered}\mathrm{by}thew\mathrm{heel}\mathrm{in}1\mathrm{revolution}=242\mathrm{cm} \\ \therefore \mathrm{Distance}\mathrm{covered}\mathrm{by}thew\mathrm{heel}\mathrm{in}500\mathrm{revolution}s=(500\times 242)\mathrm{cm} \\ =121000\mathrm{cm} \\ =1210\mathrm{m}(100\mathrm{cm}=1\mathrm{m}) \\ =1.21\mathrm{km}(1000\mathrm{m}=1\mathrm{km}) \end{gathered}$$