Q. When the road is dry and coefficient of friction is $\mu$, the maximum speed of a car in a circular path is 10 $ms^{- 1}$. If the road becomes wet and $\mu^{'} = \mu/2$, what is the maximum speed permitted?
A) 5$\ ms^{- 1}$
B) 10$\ ms^{- 1}$
C) 10$\sqrt{2}\ ms^{- 1}$
D) 5$\sqrt{2}\ ms^{- 1}$
Explanation
(d) The maximum speed without skidding is
$v = \sqrt{\mu\ rg}$
$\therefore$ $\frac{v_{2}}{v_{1}} = \sqrt{\frac{\mu_{2}}{\mu_{1}}} = \sqrt{\frac{\mu/2}{\mu}} = \frac{1}{\sqrt{2}}$
$v_{2} =$ $\frac{v_{1}}{\sqrt{2}} = 5\sqrt{2}\ ms^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.