Question

A motorcycle 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) increases
(b) decreases
(c) remains the same
(d) fluctuates

Answer 1

decreases. because it is a round bridge so opposes the bike

Answer 2

Refers to the attachment for the answer.

Answer ⇒ From the figure, Normal Reaction of the Motor cyclist is shown below,  

   mgcosθ - N =  mv²/r

⇒ N = mgcosθ - mv²/r

Now, m, v and r will be constant this means they will have the same value throughout the motion. On the other hand, The angle which the line joining the motorcyclist makes with the vertical keeps on deceasing as result cosine value is increasing, since it increases from 90° to 0°.

As a result, Normal Reaction is increasing continuously.

Hence, the answer is Option (a).

Hope it helps.