Virginia Tech > College of Science > Physics Dept > Tatsu Takeuchi > Special Relativity > Practice Problems > Problem 8
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The Enterprise and the Klingon Battle Cruiser 2

A Klingon Battle Cruiser is equiped with a disruptor cannon mounted on its rear end which can only fire perpendicularly to its direction of motion. It flies by the Starship Enterprise, which is the same length as the Battle Cruiser when both are at rest, and fires its cannon. Assume that the Battle Cruiser flies by so closely that you can neglect the time its takes for the disruptor beam to travel from the cannon to the Enterprise.

Answer the following questions:

  1. A standard Klingon tactic is to fly by its enemy and fire the disruptor cannon as the front end of the Battle Cruiser passes the enemy ship's rear end (in the Battle Cruiser frame of reference). At which spacetime point, labeled A through P, does the front end of the Battle Cruiser fly by the rear end of the Enterprise?
  2. At which spacetime point, labeled A through P, is the disruptor cannon fired?
  3. Is the Enterprise hit? Explain, referring to the spacetime diagram.
  4. The tactic assumed above is actually unrealistic since there is no way for the gunner at the rear end of the Battle Cruiser to know when the Cruiser's front end has reached the rear end of the Enterprise. So instead, consider the situation in which a light signal is sent from the front end of the Battle Cruiser to its rear when a sensor detects the rear end of the Enterprise pass by, and the cannon fires when it receives this signal.
    At which spacetime point, labeled A through P, does the cannon fire in this case?
  5. Is the Enterprise hit this time? Explain, referring to the spacetime diagram.
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