Figure 11.2a : Do this.Figure 11.2b : Don’t do this.Problems involving graphical analysis can be tricky because they require you to think abstractly about an
object’s motion. For practice, let’s consider one of the most common velocity–time graphs you’ll see:
A ball’s velocity as a function of time is graphed below. Describe with words the ball’s motion. (The
positive direction is up.)Whenever you have to describe motion in words, do so in everyday language, not physics-speak. Don’t
say the word “it”; instead, give the object some specificity. Never say “positive” or “negative”; + and −
merely represent directions, so name these directions.^5
In this case, let’s consider a ball going up (positive) and down (negative). Here’s how we’d answer