When a spring hangs an object of 0.5N for 12cm and an object of 1n for 14cm, the original length of the spring will be the same______ ．

When the weight is hung at the lower end of the spring, the tension of the spring is equal to the gravity of the weight. According to Hooke's law, △ f = k △ x, therefore, k = △ f △ x = 1 − 0.514 − 12n / cm = 0.25n/cm, when the weight is 0.5N, the length of the spring is 12cm

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1. The length of a spring is 12cm when there is no weight on the lower end, 15cm when there is a 0.6N object on the lower end and the spring is stationary. When there is a 1n weight on the lower end of the spring, the length of the spring is () A. 5 cmB. 17 cmC. 20 cmD. 7 cm
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