Question

the diameter of a cycle wheel is 21 cm how many revolutions will it take to travel 1.98 km

Answer 1

Diameter = 21 cm
radius of wheel = 21/2 cm
diatance covered in 1 revolution = circumference of wheel = 2 pi r = 2×22/7 ×21/2 = 66cm
total distance = 1.98 km = 1.98×1000m= 1.98×1000×100cm = 198000 cm

Hence number of revolutions = total distance / distance covered in 1 revolution
= 198000/66
=3000 revolutions