3is it mg
There is a parabolic shaped bridge across a river of width 100m. The highest point of the bridge is 5m above the level of the banks. A car of mass 1000kg is crossing the bridge at a constant speed of 20m/s. Find the force exerted on the bridge by the car when it is at the highest point of the bridge.
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9 Answers
33Find the radius of curvature of bridge at upper part...
Then N+mg=mv2/R...........R is radius of curvature...
So this will give N and it will be less than mg :)
Hope its clear sankara.......
3priyam mg is the only force exerted by the car on the bridge.correct me if i wrong
33If N is force by bridge on car then by newtons action reaction.... N is force by car on bridge..
mg is force on car by Earth..
Wait i am posting soln..
33First write eqn of the bridge.. then
One method is that use the formula for it..
R=[1+(dy/dx)2]3/2/d2y/dx2
or use some physics...
eqn of projectile is
y=xtanα-(gx2/2u2cos2α)
so at highest point by force balance...(mu*cosα)2/R=mg
so R is u2cos2α/g
so compare it with equation and compare and see what will be radius of curvature for the bridge...
Not complete soln though...
But U can use that formula more easily....
:P
3thnxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Priyam for clearing my doubt
