7p The spring constant for a helical coil spring, k, theoretically follows the form shown where d (lower case) is the wire diameter, D (UPPER CASE) is the mean diameter of the coil, na is the number of active coils and G is a material property called the shear modulus. Assume the following AVERAGE measurements: Out side diameter D = 23 mm Wire diameter d = 1400 microns Active coils na = 55 Modulus G = 65 kN/sq.mm. Also assume that all the measurements have an uncertainty of 2.8 % of the average. Use the High-Low method to determine (a) k and (b) delta-k, the uncertainty in k in N/m. Refer to online source for definition of 'mean diameter of coil spring'. Algebraic solution is not required but SHOW ALL 8 SUPPORTING WORK. 9 OD 23 d na 1400 55 G 65 PC (%) 2.80