Springs in parallel
Materials - OCR A-Level Physics
- Springs in parallelSprings side by side sharing the load. Combined stiffness: k_total = k₁ + k₂.: $k_{total}$ = k_1 + k_2. The springs share the load, so the combination is stiffer
- Springs in seriesSprings end to end. Combined stiffness: 1/k_total = 1/k₁ + 1/k₂.: $\frac{1}{k_{total}$} = $\frac{1}{k_1}$ + $\frac{1}{k_2}$. Each spring extends by the full force, so the combination is less stiff
- These rules are the OPPOSITE of resistors in series and parallel
- For identical springs: parallel gives $k_{total}$ = nk; series gives $k_{total}$ = k/n
Common Mistake
MEDIUM
Students often: Watch out: Apply the resistor combination rules to springs (adding in series, reciprocal in parallel).
Instead: Springs combine the OPPOSITE way to resistors. Springs in parallel: k values add directly (stiffer). Springs in series: use the reciprocal formula (less stiff).
Instead: Springs combine the OPPOSITE way to resistors. Springs in parallel: k values add directly (stiffer). Springs in series: use the reciprocal formula (less stiff).