How Much Force Do Pillars Exert with a Parked Car on a Bridge?

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SUMMARY

The discussion focuses on calculating the forces exerted by two pillars supporting a uniform bridge under the weight of a parked car. The bridge measures 20 meters in length and weighs 400,000 N, while the car weighs 19,600 N and is positioned 8 meters from one end. The correct calculation involves using the formula (Fgb*L/2 + Fgp*d)/L(sin theta) to determine the forces on each pillar, emphasizing the importance of accurately identifying distances from the pivot point. The initial calculation of 207,840 N is incorrect due to misidentified distances, particularly the distance from the car to the chosen pivot point.

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Homework Statement


A uniform bridge 20 m long and weighing 4.00x10^5N is supported by two pillars located 3 m from each end. If a 1.96x10^4 N car is parked 8 m from one end of the brige, how much force does each pillar exert?


Homework Equations


(Fgb*L/2+Fgp*d)/L(sin theta).


The Attempt at a Solution


4x10^5*10+1.96x10^4*8/20(sin 90)=207840
That's what I got as an answer. I don't know if this is correct though. Any help is appreciated. Thank you.
 
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No you don't have all of your distances right. The car is 8 m from one end, but how far is it from the pivot point you've chosen (one of the pillars)? Also, the distance of the normal force of the pillar to the pivot point is not 20 m. Draw a diagram and label everything carefully.

Repeat for the other pillar, the answer will be different.
 

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