# Why bridges are not sraight but convex?(ref-circular motion,mechanics)

1
by Debajyoti

2014-11-07T05:13:07+05:30

### This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
When a bridge is built as a straight line.  The force exerted by a vehicle or body on the bridge is equal to the weight ( M g ) of that object.

When the bridge is constructed in a convex shape, then the objects (vehicles) moving  on the bridge go in a circular path.  Hence, the equation for balancing forces will be:

M g - M V² / R = N,                 V = velocity of the vehicle.
R = radius of curvature of the bridge
N = normal force exerted by bridge on the vehicle

Hence the force exerted by vehicles (called the load) is less by the centripetal force.  Thus the stress on the bridge reduces.  Hence the stability of the bridge is better.  Also, the bending of the bridge is lessened as compared to the straight line bridges.

click on thank you link pls