# physics

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An observer measures the length of an object. In which of the following cases is the measured length at a minimum?
a. The observer and the object move with the same speed v in the same direction.
b. The observer and the object move with the same speed v in the opposite direction.
c. The observer and the object move with the same speed v in perpendicular directions.
d. The observer moves at an angle 30° to the direction of the object, but both move with the same speed.

• physics -

Case (b), which has the highest relative velocity (2v), and the greatest relativistic length contraction.

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