Question

a bicycle wheel makes 5000 revolutions in moving 11km.the diameter of the wheel in cm is?

Answer 1

In 1 revolution bicycle will cover 2πr distance.
in 2 revolution, distance will be 2πr×2 = 4πr
so in 5000 revolution distance = 2πr×5000
and this will be equal to 11Km
so 2πr × 5000 = 11×1000×100 cm
2×(22/7)× r = 1100/5
4r/7 = 20 so r = 5×7 = 35 cm
so radius = 35 cm.
Diameter = 2r = 35×2=70cm

Answer 2

Convert 11 km to cm:

11 km = 11 x 1000 = 11000 m = 11,000 x 100 = 1,100,000 cm

Find the distance covered in 1 revolution:

5000 revolutions = 1,100,000 cm

1 revolution = 1,100,000 ÷ 5000 = 220 cm

Find the diameter of the wheel:

Distance = πD

220 = πD

D = 220 ÷ π = 70 cm

Answer: The diameter is 70 cm