You know I like demos, right? This one is quite fun to do even in a class. The basic idea is to take a bucket of water and swing it around in a circle over your head. Simple, but if you have never done this one, it can be a little intimidating. Here is an example.
So, how does this work? What does it show? Really, the question is: why doesn’t the water fall out of the bucket?
First, I like to talk about “fall” what does that mean? I guess that means that the object has a downward gravitational force, but no force upward to give it a zero acceleration. Here is an example of a falling object.
In this case with the gravitational force as the only force, then the acceleration would be -9.8 m/s2. Thus falling
Now what about the water in the bucket? Here is a diagram while the bucket is over the head.
At it’s slowest speed, the water in a sense is falling. But this is different the the first ball in that the water is almost moving horizontally. You could do this with the ball also. Throw a ball over someone’s head. While over the head it is also falling, but it doesn’t hit.
Notice that I am trying to explain this so that you don’t need a lot of physics to understand it. The point is that the water is falling. Another important point is that gravity is still there. It is not being canceled or anything crazy like that.