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

• Correct answer
  A

  increases
• B

  decreases
• C

  remains the same
• D

  fluctuates erratically

Solution

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.

Hence, the correct answer is option: 'A'.