Question

The wheels of the locomotive of a train are 2.1 m in radius. They make 75 revolutions in one minute.

Answer 1

Radius of the wheel =   2.1 m

Circumference of the wheel = 2πr

`=2xx22/7xx2.1`

= 13.2 m

Distance covered by the wheel in 1 revolution = 13.2 m

Distance covered by the wheel in 75 revolutions `=(13.2xx75)=(990xx1/100)"m" `

`=(990xx1/1000) "km"`

Distance covered by the wheel in 1 minute = Distance covered by the wheel in 75 revolutions `= 990/1000 "km"`

∴ Distance covered by the wheel in 1 hour `=990/1000xx60`

= 59.4 km / h