Momentum Calculator

Calculate linear momentum from mass and velocity

Your result will appear here.

About the Momentum Calculator

Momentum combines mass and velocity into one quantity that describes motion. Unlike kinetic energy, momentum depends linearly on velocity and includes direction through the sign or vector direction of velocity.

It is especially useful in collision and impulse problems, where total momentum of an isolated system is conserved even though individual objects change speed.

How to Use the Momentum Calculator

  1. Enter object mass.
  2. Enter velocity, including the intended direction convention when signs are used.
  3. Calculate momentum.
  4. For collision problems, calculate each object’s momentum consistently before adding vector components.

How the Calculation Works

Linear momentum is p = mv, where m is mass and v is velocity.

Impulse is related by Δp = FΔt for a constant or average force over a time interval, linking momentum change to force and time.

Worked example

Momentum Calculator Worked Example

1,500 kg car moving at 12 m/s

Momentum = 1,500×12 = 18,000 kg·m/s. If the chosen positive direction is reversed, the same speed in the opposite direction would be represented with negative momentum.

Result guide

Understanding Your Momentum Calculator Result

Momentum depends on direction as well as magnitude. Equal-and-opposite momenta can sum to zero even though both objects are moving. In collision analysis, total system momentum can stay constant even while each object’s individual momentum changes dramatically, provided external impulse is negligible.

Before you rely on the answer

Assumptions and Limitations

  • Classical mechanics is appropriate.
  • Mass is constant over the calculation.
  • Velocity direction is represented consistently.

Practical tip

Using This Result in Practice

In one-dimensional collision problems, choose a positive direction before entering values and keep that sign convention for every object. When masses differ greatly, compare momentum rather than velocity alone; a slower heavy object can carry more momentum than a much faster light one.

Related calculations

Useful Calculations to Continue With

If you also need the energy associated with the motion, use the Kinetic Energy Calculator.

If momentum changes because a force acts over time, use the Force Calculator alongside the impulse relationship.

Common questions

Momentum Calculator FAQ

What is the momentum formula?

p=mv, mass multiplied by velocity.

Can momentum be negative?

Yes. The sign can represent direction in a one-dimensional coordinate system.

Is momentum conserved in every collision?

Total momentum is conserved for an isolated system, although external forces can change system momentum.