The diameter of a wheel is 70 cm. It completes 600 revolutions in 1 minute. The speed, in km/h, of the vehicle is:(Take $π =\frac{22}{7}$)

79.2

We know that,

Circumference of a circle = 2 π r

Given,

The diameter of wheel = 70cm

So, the Radius of wheel, r = 35 cm

Revolutions in 1 minute =  600

Circumference of the wheel = 2 × \(\frac{22}{7}\)× 35 = 220 cm

Distance covered in 1 revolution = 220 cm

So, distance covered in 1 minute = 220 × 600 = 132000 cm

= 13200cm = 1.32 km

Distance covered in 1 minute = 1.32 km

Hence, distance covered in 1 hr = 1.32 × 60 = 79.2 km