A boy is cycling such that the wheels of the cycle are making 140 revolutionsper minute. If the diameter of the wheel is 60 cm, calculate the speed perhour with which the boy is cycling.

we know that,

circumference of a circle = 2πr

where 'r' is the radius of the circle.

⇒ The circumference of the wheel = 2π(30)

[As 1 m = 100 cm]

As,

The distance covered in 1 revolution = the circumference of the wheel ∴ The distance covered in 140 revolution ⇒ Distance covered in 1 minute(60 seconds) = 264 m

Also, Speed

⇒ Speed of cycle (in m/s) m/s

⇒ Speed of cycle (in km/h) km/h

[As 1 hour = 3600 seconds and 1 km = 1000 meters]