IB HL Physics Spacetime Diagrams

A tutorial sheet on spacetime diagrams follows.

1. Define the term worldline.
2. Describe the path of a photon on a spacetime diagram.
3. Are unit intervals on each spacetime axis in the same inertial reference frame the same length when measured with a ruler?
4. Are unit intervals on each spacetime axis in the different inertial reference frames the same length when measured with a ruler?
5. A particle P moves at a constant velocity 0.8c relative to an inertial reference frame S. Draw the worldline of P in the reference frame of S.
6. A particle Q moves at a constant velocity 0.8c relative to an inertial reference frame S'. Reference frame S' is moving at a constant velocity of 0.6c relative to a reference frame S. Draw the worldline of Q in the reference frame S.