Imagine you are holding a bucket full of water, that collectively weighs 10 kilograms. Your arm, that you are holding the bucket with, is 5 meters long, theoretically. You decide you want to swing the bucket of water vertically, and observe that the water stays in the bucket, even at it's uppermost point. However, you are tired, so you don't want to swing it faster than you have to. So you want to know the slowest velocity in which you can swing the bucket, without any water spilling out. Let's use a formula, Fr=mv²/r, to find the solution.