Popular conversions
1 pairsKilogram-Meter per Second ↔ Newton-Second
kg·m/s ↔ N·s
Unit guides
2 unitsDetailed guide to Momentum
Momentum measures the 'quantity of motion' of an object and is calculated as mass times velocity: p = m × v.
Kilogram-meter per second is the SI unit of momentum, and newton-second — the unit of impulse — is dimensionally identical to it.
- Physical quantity
- Momentum
- SI unit
- Kilogram-meter per second
- SI symbol
- kg·m/s
- Formula
- p = m × v
- Typical use
- Collision analysis, propulsion and impact calculations
What is momentum?
Momentum is a vector quantity that combines an object's mass and velocity, describing how much 'motion' it carries.
A heavy, fast-moving object has more momentum than a light, slow one — this underlies collision and impact analysis.
Conservation of momentum
In a closed system with no external net force, total momentum before and after a collision is equal — the foundation of collision analysis.
This principle also explains rocket propulsion: expelling mass at high speed in one direction gives the rocket momentum in the other.
Momentum and impulse
Impulse is the effect of a force applied over time and is measured in newton-seconds; the impulse-momentum theorem states that impulse equals the change in momentum.
Because a newton equals 1 kg·m/s², one newton-second is dimensionally identical to one kilogram-meter per second, so the two units convert one-to-one.
Momentum units
| Unit | Symbol | Information |
|---|---|---|
| Kilogram-Meter per Second | kg·m/s | View unit guide |
| Newton-Second | N·s | View unit guide |
Sources
The definitions and conversion relationships on this page are aligned with standard metrology and SI reference material.