I'm working on a homework problem in Mathematica. We have to graph the height and the velocity of a function given an initial height and initial velocity. However, when I do the graph for the [velocity](http://en.wikipedia.org/wiki/Velocity) with an initial velocity of 0 and an initial height of 100, the entirety of the velocity part of the graph is negative. Shouldn't the velocity be increasing as the object falls?

![](https://i.stack.imgur.com/afEh6.png)

That is the graph and functions I am using. I have a feeling either something is typed wrong that I have overlooked in my numerous attempts to find it, or that there's something I'm just not understanding about what the graph is actually telling me.