Worksheet: Simultaneity

In this worksheet, we will practice using the Lorentz transformation to calculate the inertial reference frame in which two events are observed to occur simultaneously.


Two astronomical events are observed from Earth to occur at a time of 0.30 s apart and a distance separation of 2.0×10 m from each other. How fast must a spacecraft travel from the site of one event toward the other to make the events occur at the same time when measured in the frame of reference of the spacecraft?

  • A1.7×10 m/s
  • B2.5×10 m/s
  • C2.9×10 m/s
  • D2.1×10 m/s
  • E1.4×10 m/s


An observer sees two events 2.50×10 s apart at a separation of 700 m. How fast must a second observer be moving relative to the first to see the two events occur simultaneously?

  • A0.011𝑐
  • B0.110𝑐
  • C0.250𝑐
  • D0.010𝑐
  • E0.025𝑐


Two astronomical events are observed from Earth. The time difference between the observation of the events is 2 s and the observed distance between the events is 2.5×10 m.

Determine the separation Δ𝑆 of the two events.

  • A4×10 m2
  • B6×10 m2
  • C3×10 m2
  • D6×10 m2
  • E2×10 m2

Determine whether the separation of the two events is space-like or time-like.

  • ATime-like
  • BSpace-like

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