question_answer

A motor cycle is going on an over bridge of radius R. The driver maintains a constant speed. As the motor cycle is ascending on the over bridge the normal force on it:

A) In creases                          

B) decreases                      

C) remains the same            

D) fluctuates erratically

Correct Answer: A

Solution :

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