Springs in Series:
Figure illustrate two springs connected in series. The springs are provided end to end.
Figure: Springs in Series
In this case
(a) The load carried by each of the spring is the simialr as that carried by the compound spring
W1 + W2 = W
(b) The total deflection is equal to the addition of the deflection in each of the spring.
i.e.
Δ= Δ1 + Δ2
Δ / W = Δ1/ W + Δ2/ W
∴ 1/ K = 1/ K1 + 1/ K2