The Hypocrisy of Traditional Tests

TL;DR Traditional tests require students to work a few (hopefully) appropriately chosen, illustrative problems to demonstrate proficiency. What does it matter if they do these few problems early in the semester or later in the semester? What does it matter if they do them with us watching or not? What makes one essentially random problem […]

Read More The Hypocrisy of Traditional Tests

Conceptual Understanding in Introductory Physics XXXVI: Geometry and Work

This question is particularly revealing in that it assesses whether or not students understand the coordinate-free nature of work as a dot product. Be prepared to hear such nonsense locutions as “negative force” or “negative displacement” but don’t be shocked when you hear them. I think it’s a product of the relatively poor treatment vectors […]

Read More Conceptual Understanding in Introductory Physics XXXVI: Geometry and Work

Conceptual Understanding in Introductory Physics XXXV: Free-body Diagrams

Free-body diagrams are ubiquitous in introductory physics courses. They should be straightforward, but I’ve noticed that student frequently struggle with them at first because they want to include velocity or momentum in addition to forces. For this question, choose an arbitrary (the more arbitrary, the better) physical situation. It could be something from your or […]

Read More Conceptual Understanding in Introductory Physics XXXV: Free-body Diagrams

Conceptual Understanding in Introductory Physics XXXIV: Parallel and Perpendicular Components of Force

Draw an arrow representing an arbitrary force vector and another arrow representing an arbitrary momentum arrow. Label both arrows. Ask the student to perform the following task: Decompose the force vector into a component parallel to the momentum vector and a component perpendicular to the force vector. Tell whether or not the given force will […]

Read More Conceptual Understanding in Introductory Physics XXXIV: Parallel and Perpendicular Components of Force

Conceptual Understanding in Introductory Physics XXXIII: Drawing Systems

The instructor draw a random diagram showing an arbitrary number of interacting (e.g. gravitationally) entities (e.g. stars, asteroids, etc.) represented as numbered dots. The student is asked to perform the following tasks: Draw a system boundary such that the system experiences a net external force. Name each entity that contributes to this net external force. […]

Read More Conceptual Understanding in Introductory Physics XXXIII: Drawing Systems