Question

The diameter of a wheel of a bus is 90cm which makes 315 revolutions per minute. Determine its speed in kilometers per hour. {USE π = 22/7}

Answer 1

Given diameter = 90cm. Then the radius will be r = 45cm.

Distance in 1 revolution = 2pir

                                        = 2 * 22/7 * 45

                                        = 1980/7

                                        = 282.8.

 
Distance covered in 315 revolutions = 315 * 282.8

                                                             = 88987.5

                                                             = 889.875m


Speed = 889.875/1000 * 60 km/hr

            = 53.4 km/hr.


Hope this helps!