Relativity - Length Contraction Problem

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SUMMARY

The discussion revolves around the relativistic length contraction problem involving two spaceships traveling at different speeds. The key equations used include the length contraction formula, L' = L*Sqrt(1-v^2/c^2). The user calculated the ratio of the lengths of the two ships at rest, arriving at 1.01918, while the teacher provided the correct answer of 0.9823, indicating that the first ship, which travels faster, is actually shorter when at rest. This highlights the counterintuitive nature of relativistic effects on length and speed.

PREREQUISITES
  • Understanding of special relativity principles
  • Familiarity with the length contraction formula
  • Basic knowledge of velocity and time calculations
  • Concept of reference frames in physics
NEXT STEPS
  • Study the implications of Lorentz transformations in special relativity
  • Explore examples of length contraction in different reference frames
  • Learn about relativistic velocity addition and its effects
  • Investigate the concept of simultaneity in special relativity
USEFUL FOR

Students of physics, educators teaching special relativity, and anyone interested in understanding the effects of speed on physical dimensions in relativistic contexts.

Jacob Ward
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Homework Statement


You are watching a race between two space ships who pass you moving at different constant speeds. In your reference frame, both ships are the same length while moving. It takes the first ship 26.8 minutes to get to the finish line a distance 14 light-minutes away. It takes the second ship 28.2 minutes to travel the same distance. What is the ratio of the length of the first ship to that of the second ship when they are both at rest?

Homework Equations


L' = L*Sqrt(1-v^2/c^2)

The Attempt at a Solution


TimeShip1 = 26.8 (*in minutes*);
TimeShip2 = 28.3 (*in minutes*);
DistanceOfRace = 14 (*in light-minutes*);
VelocityShip1 = DistanceOfRace/TimeShip1;
VelocityShip2 = DistanceOfRace/TimeShip2;
LengthShip1 = ?
LengthShip2 = ?

L'=LengthShip1*Sqrt[1 - (DistanceOfRace/TimeShip1)^2] =
LengthShip2*Sqrt[1 - (DistanceOfRace/TimeShip2)^2]

LengthShip1/LengthShip2 = (1/Sqrt[1 - (DistanceOfRace/TimeShip1)^2])/(1/
Sqrt[1 - (DistanceOfRace/TimeShip2)^2]);

I get an answer of 1.01918 but my teacher says the answer is 0.9823 which is exactly the inverse.
This doesn't make sense to me conceptually because if the first ship is going faster (less time to complete the race) it's length should be contracted more which means it is naturally longer than ship 2 and therefore the ratio of ship 1 to ship 2 should be greater than 1 right? which would support my answer.
 
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I agree that the ratio should be greater than 1 and I agree with your reasoning. (I haven't check the numerical answer.)
 
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