1D Collisions

Elastic, inelastic, perfectly inelastic.

Concept

1D Collisions is a foundational idea in this chapter. The defining relationship is:

$v_1' = \frac{(m_1-em_2)u_1 + m_2(1+e)u_2}{m_1+m_2}$

Coefficient of restitution e = (v_2' - v_1')/(u_1 - u_2).

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 $v_1' = \frac{(m_1-em_2)u_1 + m_2(1+e)u_2}{m_1+m_2}$ and one canonical example.
• See the chapter index for full derivations, traps and exam-grade problems.