- After it became clear that the Michelson-Morley Experiment was yielding a null result the physicists Lorentz and Fitzgerald (independently) suggested that the arm of the interferometer that pointed in the direction of the ether wind was being shortened by a factor . Show that this would explain the null result. (6 marks)
- In class we derived the first half of the Lorentz Transformation equations. Your turn - please show that:
(6 marks)
- You are judge in a high profile solar system terrorist crime. The evidence presented by the prosecution is that on April 1, 2047 an alleged terrorist (known to affiliate with the Free-the-Moon Liberation Front or FMLF) was caught on surveillance using what appears to be a hand-held communication device that under image enhancement appears to be a remote detonator. He is seen pressing a button on this device at the following spacetime coordinate: minutes (c =1). At event minutes, a tans-solar system cargo ship on route to the moon exploded. FMLF claimed responsibility for this act. Based on this information should you allow the prosecution to continue?(6 marks)
- Show, using the Lorentz transformations that the quantity is an invariant quantity and discuss in several sentences what this means.(6 marks)
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A Tirillian spaceship fleeing from battle passes space station DS7 at a constant velocity of 3/5 in the +x direction as seen from DS7's frame. Let this point be called Event A when the origins in both frame coincided. The Tirillians have a cloaking device making them invisible. 40 s after passing DS7 (as measured by Tirillian clocks) the Tirillians enter a dust cloud which causes the emission of an electromagnetic pulse (call this event B) which is detected by DS7. At this instant DS7 fires a photon torpedo at the Tirillian ship. Call this event C. The tirillians conclude, 80 s after passing DS7, that their entry into the cloud was likely detected and they raise their shields as a precautionary measure. Call this event D. (10 marks - 2 each)
- Draw or use the applet (Spacetime diagrams II) to show the worldlines of DS7 and the Tirillian ship as well as events A - D.
- Use Lorentz Transformations to determine when and where event B occurs in the home frame. Does the applet or your diagram show this?
- When does event C occur in the DS7 frame? When does event C occur in the Tirillian frame? Explain how you determined this.
- Which event - C or D occurs first in the DS7 frame? Which occurs first in the Tirillian frame?
- Is it possible that the Tirillians raised their shields because they somehow detected DS7's firing of a photon torpedo? Explain.
- An interstellar probes leaves Earth and accelerates at a steady 1 g for 330 days . It reaches it's maximum speed and cruises at this speed for 2 years before a 330 day deceleration of 1 g. All times are measured from the Earth frame.
(8 marks total)
- What speed did the probe reach as measured in the Earth frame? How far did the probe travel? (2 marks)
- Construct a spacetime diagram showing the worldline of the probe.(2 marks)
- How much time did this trip take as measured by the crew of their probe? (4 marks)
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