kilogram meter per second

Momentum is what collisions conserve, and its SI unit never received a person's name, a small oddity given that momentum conservation is among the most reliable laws in mechanics. The kilogram metre per second is exactly a newton second, so momentum and impulse share one unit, and force is nothing but momentum flow: a steady one newton transfers one kg·m/s every second.

Momentum and kinetic energy rank moving objects differently, and one pair makes the point better than any formula. A major-league fastball, 0.145 kg at about 42 m/s, carries around 6 kg·m/s of momentum; a 9 mm pistol bullet, 8 grams at 360 m/s, carries under 3. The ball has roughly twice the bullet's momentum while the bullet has four times the ball's kinetic energy, because momentum grows linearly with speed and energy with its square. Stopping the ball takes more total impulse; the bullet does its damage through energy concentrated onto a small area. Any intuition that treats the two quantities as interchangeable fails on exactly this comparison.

The unit's working life is in collision arithmetic, where momentum balances before and after even while kinetic energy leaves as heat and deformation. Crash reconstruction, ballistic pendulums and docking spacecraft all run on kg·m/s, and airbags exist because the impulse relation $F\,\Delta t = \Delta p$ lets the same momentum change be bought with a longer time and a smaller force.