KNS

Kilonewton-second (kN·s or kNs) is a unit of impulse or momentum change in mechanics. It represents the product of a force measured in kilonewtons and a time interval in seconds. Impulse is the time integral of force, and it equals the change in momentum of a body: J = ∫F dt = Δp.

In SI base units, 1 kN·s equals 1000 N·s, which is also 1000 kg·m/s. This makes kN·s convenient for working with large forces in engineering contexts, while still relating directly to momentum concepts.

Usage and examples

- If a force of 4 kN is applied for 0.75 s, the impulse is 3 kN·s (4 × 0.75 = 3).

- In crash testing, impulse helps quantify the severity of impacts, often expressed in kN·s to reflect both force and duration.

- In rocketry or propulsion, impulses are discussed in terms of thrust over burn time, and can be expressed in kN·s for large-value calculations.

Relation to momentum

- The impulse J equals the change in linear momentum: J = Δp = m Δv.

- If a body of mass m experiences impulse J, its velocity changes according to Δv = J / m.

Notes

- kN·s is a unit of impulse, not energy or work. It is distinct from a plain newton-second (N·s), which is the SI unit of impulse with smaller magnitudes.

- The symbol is sometimes written as kNs or kN·s; care should be taken to avoid confusion with separate uses of kN (kilonewtons) in force-only contexts.