Convert Pound-force Square Second/Foot (lbf·s²/ft) to Petagram (Pg) instantly.
About these units
Pound-force Square Second/Foot (lbf·s²/ft)
This unit is part of the British Gravitational System, where mass is defined from force rather than the other way around. It can be interpreted as an inertial mass unit, since applying 1 pound-force to it would produce an acceleration of 1 foot per second squared. Historically, before the SI system clarified the distinction between force and mass, engineering fields often used mixed systems where pounds could represent either force (lbf) or mass (lbm). The unit lbf·s²/ft was introduced to straighten out these ambiguities in dynamic calculations such as impact forces, mechanical oscillations, and safety load computations. Today, the unit survives mostly in engineering textbooks, legacy calculations, and historical documentation. It demonstrates how complex and inconsistent measurement systems once were, and why global scientific communities moved toward SI clarity.
Petagram (Pg)
A petagram, equal to 10¹² kilograms, is used almost exclusively in global environmental science and earth system modeling. Planetary-scale carbon budgets—for example, the total carbon stored in Earth's soils or forests—are expressed in petagrams. The Amazon rainforest alone holds on the order of 100 Pg of carbon. Using petagrams helps researchers track changes in Earth's climate balance and evaluate feedback loops in the carbon cycle.