Question

A motor cycle is going on an overbridge of radius $R$. The driver maintains a constant speed. As the motor cycle is ascending on the overbridge, the normal force on it

• A. increases
• B. decreases
• C. remains the same
• D. fluctuates erratically

Answer 1

Answer: (A)

From figure, reaction of normal force on the motorcyclist is
$mg\cos \theta -R=\frac{m{v}^2}{r}$
$\therefore R=mg\cos \theta -\frac{m{v}^2}{r}$
As motorcycle ascend on the overbridge, angle of inclination of motorcycle with vertical $\theta$ decreases and becomes zero at the highest point. So cosq goes on increasing and becomes 1 at highest point. So value of $R$ is continuously increasing while ascending.