Momentum calculator
Enter mass and velocity. A negative velocity means motion the opposite way, so the momentum comes out negative.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter mass, speed unit and velocity.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
p = m × v, and kinetic energy KE = p² ÷ (2m).
Example
Inputs: Mass = 1,500 kg, Speed unit = Kilometers per hour (km/h), Velocity = 36. Result: Momentum: 15,000 kg·m/s; Kinetic energy: 75,000 J.
Limits and caveats
- Newtonian formula; not valid near the speed of light.
- Works along one direction, not as a 2D or 3D vector.
Questions about this tool
What unit is momentum in?
Kilogram meters per second (kg·m/s), which equals newton seconds.
What is conservation of momentum?
In an isolated system with no outside force, the total momentum is the same before and after a collision.
Why is a truck harder to stop than a car at the same speed?
Its larger mass gives it more momentum, so stopping it needs a larger impulse: more force or more time.