Springs in series
An arrangement where springs are connected end-to-end so the same force acts on each. For springs in series, the reciprocal of the effective spring constant equals the sum of reciprocals: 1/k_eff = 1/k₁ + 1/k₂ + ... . The effective spring constant is less than the smallest individual spring constant.
Formula
1/k_eff = 1/k₁ + 1/k₂ + ...
Real World
Bungee jump operators at Bloukrans Bridge connect multiple cords in series to achieve a larger, safer total extension for heavier jumpers.
Exam Focus
Remember: series gives a smaller k_eff than either individual spring — if your answer is larger, you've used the wrong formula.
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