Question

The diameter of wheel is 0.70 m. Find the distance covered by it in 500 revolutions. If the wheel takes 5 minutes to make 500 revolutions; find its speed in:

(i) m/s

(ii) km/hr

Answer 1

Diameter =0.70 m

$\therefore$ Radius, r =0.35 m

$\therefore$ Distance covered in 1 revolution, i.e. circumference $2=\pi r$

$=2\times \frac{22}{7}\times 0.35$

=2.20 m

$\therefore$ Distance covered in 500 revolutions

$=2.20\times 500$

=1100.00 m

=1100 m

Time taken =5 minutes $=5\times 60$ =300 sec.

Speed in m/s $=\frac{1100}{300}$

$=\frac{11}{3}=3\frac{2}{3}m/s$

Again, Distance =1100 m

$=\frac{1100}{1000}$

$=\frac{11}{10}km$

Time =5 minutes

$=\frac{5}{60}hr.$

Speed in km/hr $=\frac{\frac{11}{10}}{\frac{5}{60}}=\frac{11}{10}\times \frac{60}{5}$

$=\frac{66}{5}=13.2km/hr.$

Hence 1100 m, $\left(i\right)3\frac{2}{3}$ m/s (ii)13.2 km/hr