The right answer is(c) NA <NB
Explanation:
Both points A and B are on the crest of the curves where the weight of the car 'mg' is perpendicular to the surface. But due to the movement of the car on the curve it will feel reduction in the weight by an amount mv²/r, where 'v' is the constant speed of the car and 'r' is the radius of the curve. Clearly this reduction in weight is inversely proportional to 'r' as the numerator is constant. Smaller the 'r', greater is the term mv²/r. Since 'r' at point A is smaller than at the point B, so reduction in weight will be more at A than at B. It means the apparent weight is less at A than B.
Normal forces at these points will be equal to the apparent weight at these points. So NA < NB .
