Question

A vehicle is travelling with uniform speed along a concave road of radius of curvature $19.6m$. At lowest point of concave road if the normal reaction on the vehicle is three times its weight, the speed of vehicle is:

• A. $4.9m/s$
• B. $9.8m/s$
• C. $14.7m/s$
• D. $19.6m/s$

Answer 1

The correct option is D $19.6m/s$

Given $N=3mg$

As normal reaction is three times weight, net force will balance the centripetal force:
$N-mg=\frac{m{\nu }^2}{R}$
$2mg=\frac{m{\nu }^2}{R}$
$\Rightarrow \nu =\sqrt{2gR}=\sqrt{2\times 9.8\times 19.6}$$=19.6m{s}^{-1}$