A motor cycle is going on an overbridge of radius R . The driver...

Reaction of normal force on the motor cyclist $M g \cos \theta-N=\frac{m v^2}{R}$ or $\quad N=M g \cos \theta-\frac{M v^2}{R}$ As the motor cyclist moves upward on the bridge, $\theta$ decreases and therefore, $N$ increases and becomes maximum at the highest point.