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