Question

The wheel of a motorcycle is of radius 35 cm. How many revolutions per minute must the wheel make so as to keep a speed of 66 km/hr ?

Answer 1

Circumference = 2πr

= 2x(22/7)x35

= 220 cm = 2.2 m
(converted from cm to m)
Speed = 66 km/hr

= 66 x(5/18) m/s
( converted from km/hr to m/s)

Distance travelled in 1 min= 66 x (5/18) x 60 m/min= 1100 m

Now, number of revolutions = distance in one min /circumference of the wheel.

N= 1100/2.2 = 500 revolutions per minute.