Question

2) Two identical cars 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)
1)1:3
2)1:2
3)2:3
4)1:5
​

Answer 1

Answer:

Correct option is

A

1:3

Velocity, v=36×

18

5

=10ms

−1

Centripetal force, F

c

=

r

mv

2

=

20

m×10

2

=5m

For A bridge is convex upward, normal reaction,N

A

=mg−F

c

=10m−5m=5m

For B bridge is concave upward, normal reaction,N

B

=mg+F

c

=10m+5m=15m

N

A

:N

B

=5m:15m=1:3