A truck comes to a 1000-ft.-long bridge and stops right before going onto it to read a sign. The sign says that the maximum weight the bridge can hold is 4 tons, which is the exact weight of the truck. So the truck starts going towards the bridge. About halfway over the bridge a little bird lands on the top of the truck. Does the bridge break?
Answer
No, because by the time the truck is halfway across the bridge it has burned enough gas which brings its weight down to let the bird sit on it without the bridge breaking.
