Relative Velocity in 1D & 2D

v_AB = v_A - v_B.

Concept

Relative Velocity in 1D & 2D is a foundational idea in this chapter. The defining relationship is:

$\vec v_{AB} = \vec v_A - \vec v_B$

Subtract vectors graphically (head-to-tail).

Worked Application

Apply the formula to a typical problem from your textbook. Identify the knowns, plug into the equation, and check that the units work out. Always sanity-check the magnitude before accepting an answer.

Common Confusions

• Confusing the variables in the formula — re-read the symbol definitions in the chapter.
• Forgetting unit conversions (cm vs m, g vs kg).
• Ignoring sign conventions where direction matters.

Key Takeaways

• Master the formula $\vec v_{AB} = \vec v_A - \vec v_B$ and one canonical example.
• See the chapter index for full derivations, traps and exam-grade problems.