An apple. They fall off trees and can be sweet or bitter depending on the type of apple. Most people buy apples, but you can get a free one if you have an apple tree. In olden days apples were used to throw at a person you loved, and in 2013 the company, Apple, pushed past Exxon Mobile to have the largest market capitalization in the United States.
An 18-wheeler is crossing a 4 kilometer bridge that can only support 10,000 kilograms and that’s exactly how much the rig weighs. Halfway across the bridge a 30 gram sparrow lands on the cab, but the bridge doesn’t collapse. Why not?
Since the bridge is 4 kilometers long, the halfway point would be 2 kilometers. The 18-wheeler would have used much more than 30g of fuel to drive 2 kilometers.