Question

a bicycle wheel makes 5000 revolutions in moving 10km. Find the radius of the wheel

Answer 1

Number of revolution = 5000
Distance = 10 km = 10000 m

Circumference of wheel = Distance /Number of revolution
Circumference of wheel = 10000 / 5000
2*pi *r = 2
=> 22r/7 = 1
r = 7/22 m
r = 700/22 cm

Radius of wheel 9.1 cm

Answer 2

distance = 10 km = 10000 m
no.of revolutions = 5000
the wheel would rotate along its circumference, so
5000 revolutions take 10000 m
1 revolution take 10000/5000 = 2 m
So circumference = 2 m
circumference = 2πr
2πr = 2
πr = 1
r = 1/π =1/(22/7) = 7/22 = 0.32 m approximately
r = 32 cm approximately.