question_answer

Given that

d = diameter of spring.

R = mean radius of coils.

n = number of coils, and

G = modulus of rigidity.

The stiffness of the close-coiled helical spring subject to an axial load W is equal to:    

A) \[\frac{G{{d}^{4}}}{64{{R}^{3}}n}\]           

B) \[\frac{G{{d}^{3}}}{64{{R}^{3}}n}\]

C) \[\frac{G{{d}^{4}}}{32{{R}^{3}}n}\]           

D) \[\frac{G{{d}^{4}}}{64{{R}^{3}}n}\]