Momentum Calculator

Calculate linear momentum and the impulse required to change it.

About Momentum Calculator

Momentum change equals force times time, so extending the duration of a collision reduces the peak force proportionally. That is the entire principle behind crumple zones and airbags. A crash that takes twice as long to stop halves the average force on the occupants, which is why stopping distance matters more than speed alone.

Formula

Momentum

p = m v; impulse–momentum: F Δt = Δp

p: Momentum in kilogram metres per second
Δt: Duration of the force

Worked example

With the default values below, Momentum Calculator returns Momentum of 30,000.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Massminimum 0 kg: 1,500 kg
Velocityminimum -200 m/s: 20 m/s
Final velocityminimum -200 m/s: 0 m/s
Time over which it changesminimum 0.001 s: 0.15 s

Results

Momentum: 30,000.00 kg m/s
Final Momentum: 0.00 kg m/s
Change in Momentum: -30,000.00 kg m/s
Average Force Required: -200,000.00 N
Change in Kinetic Energy: -300,000.00 J

Step by step

1Values used
2Momentum
3Momentum= 30,000.00 kg m/s
4Final Momentum= 0.00 kg m/s
5Change in Momentum= -30,000.00 kg m/s
6Average Force Required= -200,000.00 N
7Change in Kinetic Energy= -300,000.00 J

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Momentum calculated?

p = m v; impulse–momentum: F Δt = Δp Momentum change equals force times time, so extending the duration of a collision reduces the peak force proportionally. That is the entire principle behind crumple zones and airbags.

Why does Momentum matter?

A crash that takes twice as long to stop halves the average force on the occupants, which is why stopping distance matters more than speed alone.

What values do I need to enter?

This calculator takes 4 inputs: Mass, Velocity, Final velocity, Time over which it changes. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.