Exam-style question
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Which statement best describes length contraction in special relativity?.
- A.Length increases with speed
- B.Length decreases in the direction of motion
- C.Length remains unchanged
- D.Length depends on the observer's mass
Model answer
What a good answer should say
- Length decreases in the direction of motion
Explanation
Why this works
Formula/rule: L = L0 √(1 – v²/c²). Substitution: v = relative speed, c = speed of light.
Working: Since v²/c² > 0, √(1 – v²/c²) < 1, so L < L0. Answer: The moving object's length is shorter than its proper length.
Units/conclusion: Length contraction reduces the measured length in the direction of motion.
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