Question

The radius of a wheel is 0.25 m. The number of revolutions it will make to travel a distance of 11 km will be

विकल्प

•  2800  

• 4000

•  5500

•  7000

Answer 1

We have given the radius of the wheel that is 0.25 cm. 

We know that distance covered by the wheel in one revolution=`" Distance moved"/"Number of revolutions"`

Distance covered by the wheel in one revolution is equal to the circumference of the wheel. 

`2pi r="Distance moved"/"Number of revolutions"......(1)`

Distance moved is given as 11 km so we will first convert it to m.

∴ 11 km = 11000 m

Now we will substitute the values in equation (1),

`2xxpixx0.25=11000/"Number of revalution"`

Now we will substitute pi=`22/7`

`2xx22/7xx0.25=11000/"Number of revolutions"`

Simplifying equation (1) we get,

`∴" Number of revolutions"=(11000xx7)/(2xx22xx0.25)`

`∴" Number of revolutions"=(11000xx7)/(22xx0.5)`

`∴" Number of revolutions"=(1000xx7)/(2xx0.5)`

`∴" Number of revolutions"=7000/1`

`∴" Number of revolutions"=7000`

Therefore, it will make `7000` revolutions to travel a distance of 11 km.