The diameter of front and rear wheels of a tractor are 80 cm and 2m, respectively. Find the number of revolutions that rear wheel will make in covering a distance in which the front wheel makes 1400 revolutions.
Given: d1 = 80 cm
d2 = 2 m
To find: Number of revolutions by rear wheel.
Explanation:
Diameter of front wheels = d1 = 80 cm
Diameter of rear wheels = d2 = 2 m = 200 cm
Let r1 be the radius of the front wheels = r1 = 80/2 = 40 cm
Let r2 be the radius of the rear wheels = r2 = 200/2 = 100 cm
Now, Circumference of the front wheels = 2πr1
= 2 × (22/7) × 40
= 1760/7 cm
Circumference of the rear wheels = 2πr2 = 2 × (22/7) × 100 = 4400/7 cm
No. of revolutions made by the front wheel = 1400
∴ Distance covered by the front wheel = 1400 × (1760/7) = 352000 cm
Number of revolutions made by rear wheel in covering a distance in which the front wheel makes 1400 revolutions = 
= 
= 560 revolutions.