Question

The wheels of a car are of diameter $60cm$ each how many complete revolution does each wheel make in $10$ minutes when car is travelling at a speed of $66km$ per hour.

Answer 1

Speed of the car $=66km/hr$

$\therefore$ Distance travelled by the car in $1hr$ or $60$ minutes is $66km$

$\Rightarrow$ Distance travelled by the car in $10$ minutes is $\frac{66}{60}\times 10=11km=11\times 1000\times 100cm$

Diameter of car wheel $=60cm$

$\therefore$ radius of car wheel $=30cm$

$\therefore$ Circumference of the wheel $=2\pi r=2\times \frac{22}{7}\times 30=\frac{1320}{7}cm$

We know that,

Circumference of the wheel $=$ Distance travelled by the car when its wheels take one complete revolution $=\frac{1320}{7}cm$

$\therefore$ Number of revolutions made by wheels in $10$minutes is given by

$\frac{distancetravelledbythecar10minutes}{distancetravelledbythecarwhenitswheelstakeonecompleterevolution}$

$=\frac{11\times 1000\times 100}{\frac{1320}{7}}$

$=\frac{77\times 1000\times 100}{1320}$

$=5833$ revolutions

$\therefore$ Number of revolutions made by wheels in $10$ minutes is $5833$ revolutions