For a helical torsion sprig, the stress concentration factor at outer fibre is? Give spring index=5.$

For a helical torsion sprig, the stress concentration factor at outer

1.	For a helical torsion sprig, the stress concentration factor at outer fibre is? Give spring index=5.$
A.	0.78
B.	0.87
C.	1.87
D.	0.69
Answer» C. 1.87