Q. A car is moving on a circular level road of radius of curvature 300 m. If the coefficient of friction is 0.3 and acceleration due to gravity $10\ ms^{- 2}$, the maximum speed the car can have is (in km $h^{- 1}$)
A) 30
B) 81
C) 108
D) 162
Explanation
(c) Here, $r = 300\ m,\mu = 0.3,g = 10\ ms^{- 2}$
$v_{\max} = \sqrt{\mu\ rg} = \sqrt{0.3 \times 300 \times 10} = 30\ ms^{- 1}$
$= 30 \times \frac{18}{5}km{\ h}^{- 1} = 108\ km\ h^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.