A New Kind of World

Today in physics, the class responded to a question incorrectly but it really got me thinking. The question posed was "What is the acceleration of a ball at the peak of its path after it has been thrown up into the air?" The class answered zero with the singular thought that the ball is not moving up or down at the peak of a throw and thus, has zero acceleration. This was, of course, incorrect, as are most of our answers in IB physics. The ball has a continual downward acceleration. This got me thinking, what if the ball's acceleration was zero at the top of a throw? What if we lived in a world without the constant pull of gravity. In such a world, any object thrown would stop upon slowing down and "what goes up" would not come down. A bar would not be necessary to measure the height of jumps at high jump because the jumpers would not be able to move after their jump. In contrast, long jump would not be possible. If a car hit a bump in the road, it would no longer touch the ground, and traffic on any bumpy road would come to a screeching halt as drivers attempted to push their cars down onto the roads. Even walking would not work correctly. All building would need be made up of small tubes so that we always had a surface to push off of an thus travel forward. Any sort of travel outside would be a downright impossibility. Thank God for Gravity!