Exam-style question
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An object moves at 0.8c relative to an observer. What is the time dilation factor γ?.
- A.1.25
- B.1.667
- C.2.0
- D.3.0
Model answer
What a good answer should say
- 1.667
Explanation
Why this works
γ = 1/√(1 − v²/c²). Substituting v = 0.8c gives v²/c² = 0.64.
Hence γ = 1/√(1 − 0.64) = 1/√0.36 = 1/0.6 = 1.667. The factor is dimensionless.
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