(2) Why do spring balance shows wrong reading after they had been uses for a long time?​

This is because of continuous usage, the wire loses its elasticity and dose not regain it original dimension

When a spring balance has been used for a long time, the spring in the balance fatigued and there is loss of strength of the spring. In such a case, the extension in the spring is more for a given load and hence the balance gives wrong readings.

are there options? cause you ain’t. real specific

kepler used the data from tycho blahe (his mentor) to construct the laws of planetary motion.