Question

The wheels of a car are of diameter $140$ cm each.How many complete revolutions does each wheel make in $10$ minutes when the speed of the car is $66$ km / hr? ($use$ $\pi =\frac{22}{7}$)

Answer 1

Given radius of wheel = 70 cm

Perimeter = $2\pi r=140\pi$ cm

Speed of car = 66 km/he = $66\times \frac{5}{18}m/s$

We know speed = $\frac{distance}{time}$

Distance travelled in 10 min

$66\times \frac{5}{18}=\frac{distance}{10\times 60}$

distance = $66\times \frac{5}{18}\times 10\times 60$

distance = 11000 m=11 km$

now 1 complete revolution = $2\pi r$

Total no. of complete revolution = $\frac{11,000}{140\times \frac{22}{7}}\times 100$

$=\frac{1100000}{140\times 22}\times 7=2500$

Hence 2500 revolution complete by each Tyre in 10 m