CollegeBoard SAT Physics Study Guide PT1 Q32

CollegeBoard's Book

32) This question asks us to use the given graph to find the region when the object has a minimum magnitude of acceleration. Acceleration is the slope(also known as derivative) of our velocity graph. We can simply look at the graph and estimate the slope.

You may ask how I know that the slope between A and C is 1, or how I know that between D and E is -1. Well, for this problem, they don't ask for the acceleration, just the region where is is minimum. It is important to take away that from A to C there is a constant positive slope, from C to D there is no slope, and from D to E there is a constant negative slope with the same magnitude as from A to C.

Many people jump to answer that acceleration is at a minimum between D and E because the slope is negative. However, it is crucial to realize that the the questions asks for the smallest magnitude of acceleration. From D to E, the acceleration is just as great in magnitude as from A to C. Thus, the answer is from C to D where the slope is 0.

Answer: D