Question

In England during the Middle Ages an extensive system of canals was used for transportation. Some of these canals crossed over canyons by flowing over bridges (viaducts). Suppose that a heavily loaded barge floating down the a canal crossed over such a waterway bridge. See the pictures of examples of thesetypes of viaducts. Which statement below is most correct.

Select one:

A. The force on the barge would become less because some water would be squeezed off of the bridge.

B. The force on the bridge would not change when the barge passed over.

C. Whether or not the force on the bridge would increase or decrease would depend on whether the water was flowing or stationary.

D. The force downward on the bridge would increase because of the added weight of the barge.

E. The force on the bridge would become less because of the buoyancy effect of the water on the barge.

Answer 1

a) incorrect.. water is being displaced but extra weight also adds up because of barge.. so force will not decrease.

b) correct.. As barge is floating, the amount of water displaced be "w" is equal to weight of barge, so force will remain same.

c) incorrect..floating or stationary won't cause any difference.

d)incorrect.. as explained in part b, it will remain same.

e)incorrect ..buoyancy effect changes apparaent weight of barge, it won't have any effect on the force experienced by bridge.