Question

A bus is moving on a circular road which is rough and banked. Which of the following forces cannot act as a source of centripetal force?

• A. Normal reaction ($N$)
• B. Frictional force
• C. Both a and b
• D. $mg$

Answer 1

The correct option is D $mg$

In the question, the bus is moving on a horizontal circular path. For this motion, net centripetal force should be acting in the horizontal direction radially i.e X-direction.

Weight of the bus ($mg$) is acting in vertically downward direction (Y-direction). Therefore, weight i.e $mg$, cannot provide the centripetal force for the motion.