A. The equivalent stiffness of two springs (of equal stiffness ‘S’) in series is S/2 while in parallel
is 2S
B. For a helical spring, deflection is proportional to D3 (D = mean coil diameter) or d4 (d = wire
diameter)
C. Crushing load or columns is less than the buckling load
D. Modulus of resilience is proportional to (stress at elastic limit)2