This topic mainly examines two aspects of knowledge: (1) The principle of using the spring dynamometer is: "The greater the force on the spring, the longer the stretch of the spring". (2) When two forces are combined in the same direction, the resultant force is equal to the sum of the two forces. The use principle of the spring dynamometer is: "The greater the force on the spring, the longer the stretch length of the spring". If each spring stretches 65438+.

The tension of each spring should be 50N, and the tension of four springs should be 200 N according to the principle of resultant force in the same direction.

Comments: The key to solve this problem is to understand the use principle of the spring dynamometer. It is necessary to know that the tension required for each spring to stretch 50cm is 50 N.