1. The problem is how to make a spring elastic potential energy is not reduced?

2. Or how to make a spring elastic potential energy to maintain the original size of the change?

3. It is proved that the elastic potential energy induced by ground stress is first of all consumed in coal solid fragmentation, which creates conditions for gas energy release from coal solid.

4. According to Hertz contact theory, this paper discussed the elastic deformation in the ball screw systems and elastic potential energy caused by it.

5. The results showed that the difference existed between male and female in elastic potential energy utilization ratio(higher for male)which positively correlated to the skill degree and body mass.

6. Hence, the loss of gravitational potential energy of the block equals the gain of elastic potential energy of the spring.

7. This paper deals with the problem of how to skilfully select spring elastic potential energy zero in applying law of conservation of mechanical energy, and makes some analyses combined with examples.