Two identical car A and B are moving at 36 kmph. A goes on a bridge, convex upward and B on concave upward. If the radius of curvature of bridge is 20 m, the ratio of normal forces exerted on the cars when they are at the middle of bridges (g=10 ms−2)
Velocity, v=36×518=10ms−1
Centripetal force, Fc=mv2r=m×10220=5m
For A bridge is convex upward, normal reaction,NA=mg−Fc=10m−5m=5m
For B bridge is concave upward, normal reaction,NB=mg+Fc=10m+5m=15m
NA:NB=5m:15m=1:3