Comparing Student Understanding of Addition of Vectors for Multiple Points of Instruction and Physical Contexts

The Physics Education Group at the University of Washington has been examining student understanding of addition of vectors throughout introductory physics. We present results from the administration of a qualitative question about the magnitudes of vector sums to students in the first, second, and third quarters of a calculus-based introductory physics course. We also compare student performance on versions of this question asked for a variety of different physical contexts, including velocity, force, and momentum.