Chapter 1, Problem 3P

The spring force F and displacement x for a close-wound tension spring arc measured as shown in Fig. P1.3.

The spring force F and displacement x satisfy the linear equation $F=kx+F_i$, where k is the spring constant and F, is the preload induced during manufacturing of the spring.

(a) Using the given data, find the equation of the line for the spring force F as a function of the displacement x, and determine the values of the spring constant k and preload F_i.

(b) Sketch the graph of F as a function of x and dearly indicate both the spring constant k and preload F_i.