122-123 What the Friction?

So we've played around with FBDs, and we're learned that lifting and pulling heavy things is easier than leaning and pushing, but can we learn more about friction and normal forces?

Let's investigate, and as we do, let's see if there is a predictable relationship between the amount of friction force and the normal force.  (Also, is friction constant, or is a little extra bump needed to get things sliding?)

122 Is your experimental setup (draw the apparatus!!!)
123 Is your data and your analysis (what does it mean?)