Convert Pound-Force to Femtonewtons
Convert Pound-Force (lbf) to Femtonewtons (fN) instantly and accurately.
Conversion Formula
fN = lbf × 4.448221615e+15
About Pound-Force
The pound-force (lbf) is the gravitational force on 1 lb-mass under standard gravity - exactly 4.4482216152605 N. It dominates US structural, mechanical, and aerospace engineering: AISC and ACI structural codes use lbf and kips (1 kip = 1,000 lbf); tire pressure 'psi' means lbf/in²; engine torque in lb·ft. Aircraft thrust is quoted in lbf: the GE90-115B (Boeing 777) produces 115,300 lbf = 513 kN. Spring rates, fastener torques, and load cell calibrations across North America are in lbf. 1 lbf = 4.44822 N = 16 ozf = 32.174 pdl.
About Femtonewtons
A femtonewton (fN) is 10⁻¹⁵ N - the force scale of single-molecule biology. RNA polymerase exerts a stall force of ~14-25 fN while transiting DNA at 10-50 bp/s. Myosin V motor proteins step 37 nm with ~1-3 fN per head. The viscous drag on a 100 nm nanoparticle moving at 1 µm/s through cytoplasm is ~0.2-0.5 fN. Optical tweezers with back-focal-plane detection resolve sub-femtonewton forces, enabling measurement of single-enzyme output. AFM receptor-ligand unbinding (e.g., biotin-streptavidin) gives adhesion forces of 100-300 fN. 1 fN = 10⁻¹⁵ N.
Quick Reference Table
| Pound-Force (lbf) | Femtonewtons (fN) |
|---|---|
| 1 lbf | 4.448 × 1015 fN |
| 2 lbf | 8.896 × 1015 fN |
| 5 lbf | 2.224 × 1016 fN |
| 10 lbf | 4.448 × 1016 fN |
| 25 lbf | 1.112 × 1017 fN |
| 50 lbf | 2.224 × 1017 fN |
| 100 lbf | 4.448 × 1017 fN |