From the question Radius of wheel = r =
![\[35\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-4c246379fe948cf04ed07be9d0c37357_l3.png "Rendered by QuickLaTeX.com")
cm
We know that one revolution of the wheel is equal to Circumference of the wheel
i.e.,
![\[2\pi r\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-43b168c86ecd60123b88746e81b15805_l3.png "Rendered by QuickLaTeX.com")
=
![\[2\times (22/7)\times 35\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-e4ec909575d5ad31299d85be9ebc695b_l3.png "Rendered by QuickLaTeX.com")
=
![\[220\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-632877eb4959a38f0266b37b3a0b47f7_l3.png "Rendered by QuickLaTeX.com")
cm
But, from the question it is given that,
Speed of the wheel is
![\[66\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-28337cbee3c1bfe56a8ff193040b617b_l3.png "Rendered by QuickLaTeX.com")
km/hr
=
![\[(66\times 1000\times 100)/60\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-ad75adfcf1b41704c8e8383433bf125b_l3.png "Rendered by QuickLaTeX.com")
cm/min
=
![\[110000\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-08d8184fb49f3750d6c6d5dba0e63916_l3.png "Rendered by QuickLaTeX.com")
cm/min
∴ Number of revolutions in one min =
![\[110000/220=500\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-b1635f7282daefe22f04da87258ab05b_l3.png "Rendered by QuickLaTeX.com")
Therefore,
![\[500\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-6ab5d1c783918e412f33f2a0d6a52a71_l3.png "Rendered by QuickLaTeX.com")
revolutions per minute should be made by the wheel make so as to keep a speed of
km/h