Physics I / Matrices and Matrix Operations
Practice question · Multiple choice

For two square matrices, ABAB and BABA are generally different. What everyday analogy captures why order matters?

Hints
  1. Matrices do things (rotate, stretch, reflect). Think of them as actions, not numbers.
  2. Rotate a book 90° then flip it; now flip first and rotate after. Compare the endings.
Show the answer

C. Socks then shoes vs shoes then socks: order composes

Why

A matrix is a transformation, and transformations compose like actions in time: rotate-then-reflect rarely equals reflect-then-rotate. Losing commutativity is the price of upgrading from numbers to actions, and non-commutativity later becomes the engine of quantum mechanics.

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