Question: I can fly like a bird not in the sky which can always swim and always dry. I say goodbye at night and morning hi I'm part of you what am I? I follow and lead as you pass. Dress yourself in black my darkness lasts. I flee the light but without the sun. Your view of me would be gone.
Answer: Your shadow
Question: A semi truck weighing exactly 10,000 pounds gets onto a bridge that is 100 miles long. The bridge's weight limit is exactly 10,000 pounds, any more will break the bridge. After going about 80 miles down the bridge a small bird lands on the truck.
Answer: Nothing, after traveling 80 miles the truck will have surely burnt enough fuel to allow the bird to land on the truck without breaking the bridge.