Student Use of Vectors in Mechanics

A functional understanding of Newton s second law as §a vector equation requires that students be able to §reason about vectors. I present data describing §students conceptual difficulties with vector §addition and subtraction, and with vector quantities §such as force, acceleration and tension. These data §suggest that after traditional instruction in §introductory physics, some students do not recognize §the vector nature of these quantities. Other §students who do not have the requisite procedural §knowledge to determine net force or acceleration, §and are therefore unable to reason qualitatively §about Newton's second law. I describe some specific §procedural and reasoning difficulties we have §observed in students use of vectors. In addition, I §describe modifications to laboratory instruction in §mechanics that we designed on the basis of our §research into student understanding. These §modifications were intended to improve students §understanding of vector addition and subtraction and §to promote student use of vectors when solving §mechanics problems. Finally, I discuss initial §measures of the effectiveness of these modifications. A functional understanding of Newton s second law as §a vector equation requires that students be able to §reason about vectors. I present data describing §students conceptual difficulties with vector §addition and subtraction, and with vector quantities §such as force, acceleration and tension. These data §suggest that after traditional instruction in §introductory physics, some students do not recognize §the vector nature of these quantities. Other §students who do not have the requisite procedural §knowledge to determine net force or acceleration, §and are therefore unable to reason qualitatively §about Newton''s second law. I describe some specific §procedural and reasoning difficulties we have §observed in students use of vectors. In addition, I §describe modifications to laboratory instruction in §mechanics that we designed on the basis of our §research into student understanding. These §modifications were intended to improve students §understanding of vector addition and subtraction and §to promote student use of vectors when solving §mechanics problems. Finally, I discuss initial §measures of the effectiveness of these modifications.