# Special Relativity test

1. ### awri

34
Today I have a test on sp. relativity. This subject is quite different for the other physics courses and thus I am unsure what to focus on. What are the most common types of questions asked about sp. relativity? Whats most important?

2. ### turin

2,326
That depends on your syllabus. Indeed, approaches to Special Relativity are quite varied, and can depend on, e.g., what you are using it for.

I try to understand SR in terms of representations (such as scalars, vectors, tensors, and how to write Lorentz transforms in matrix form) and invariants (such as the speed of light, contractions, and the metric tensor). Then, how are these things physically interpretted.

- metric (tensor): proper length/time, contraction, raising and lowering indices, invariance of
- Lorentz transform: matrix representation, system of equations, gamma and beta, raptidity, pseudo-rapidity, rotations vs. boosts, decomposition into a rotation and a boost, "2x2 matrix" representation (Pauli matrices or quaternions)
- the distinction between: proper time and coordinate time, rest mass and "relativistic mass", proper velocity and coordinate velocity

Some specific issues/applications that could appear: