Question

The diameter of the wheel of a car is $70cm$. How many revolution will it make to travel $1.65km$?

Answer 1

Given:

The diameter of the wheel of a car $\left(d\right)=70cm$

$\Rightarrow$ Radius of wheel of the car $\left(r\right)=\frac{70cm}{2}=35cm$

Circumference of the wheel $=2\pi r$

$=2\times \frac{22}{7}\times 35cm$

$=220cm$

$=\frac{220}{100}m$ [Since, $1cm=\frac{1}{100}m$]

$=\frac{11}{5}m$

So, the Circumference of the wheel is $\frac{11}{5}m$.

i.e., Car can travel $\frac{11}{5}m$ per one revolution of the wheel.

$\Rightarrow$ Number of revolutions taken by wheel to travel $1.65km$,

$=\frac{1.65km}{\frac{11}{5}m}$

$=\frac{1.65\times 1000m}{\frac{11}{5}m}$ [Since, $1km=1000m$]

$=1.65\times 1000\times \frac{5}{11}$

$=1650\times \frac{5}{11}$

$=150\times 5$

$=750$

Therefore, $750$ revolutions will be made by wheel to travel $1.65km$.