Wyvern
Khaleesi
Here is one from FBS 200
A truck is crossing a 2km bridge and weighs 3 tons. The bridge can only support 3 tons so everything is in balance. At the half way mark the driver stops and a bird lands on the truck.
Will the bridge collapse under the extra weight?
Depending on the size of the bird - small bird - no - since he would have used some petrol to get to the halfway point.
Big bird - not sure?