The upper end of a light spring is fixed on the ceiling of the elevator, and an object is suspended at the lower end When the elevator is stationary, the spring elongation is 8 cm; later, it is found that the spring elongation is 12 cm. According to this, the movement of the elevator at this time may be () A. the acceleration is g / 2 B. The acceleration is g / 2 C. The acceleration is 3G / 2

If the spring becomes longer, it must be a or D
Then according to the formula: (KX = f)
0.08k=mg
0.12k=mg+ma
The solution is a = 0.5g
Choose a

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