STEMHub.tools
Mechanics · Momentum and impulse

Linear Momentum & Impulse Calculator

Calculate signed one-dimensional momentum, impulse, momentum change, and average net force over a time interval.

Formula shown Runs locally Reviewed Aug 11, 2026
Follow us on Google
Equation guide

Signed one-dimensional momentum and the net impulse delivered over a time interval

Linear momentum

p = mv

Impulse–momentum theorem

J = Δp = pf − piJ = m(vf − vi)

Average net force

Favg = Δp/Δt1 N·s = 1 kg·m/s
Linear momentum and force impulse

Connect motion before and after a force acts

p = mv

This is a scalar, one-dimensional projection model, so no vector arrows are used. Choose a positive axis first; velocities, momentum, impulse, and average net force are positive or negative relative to that axis. Inputs and displayed results use at most three decimal places.

p = mv

Choose the unknown and enter the other two signed one-dimensional quantities.

Using the model

Symbols, assumptions and limitations

Interpretation notes

Mass is positive, while velocity, momentum, impulse, and force are signed components along a user-chosen one-dimensional axis. The average-force relation assumes the entered impulse is the net impulse over a positive time interval. For variable force, impulse is the area under the force–time curve; this calculator reports the equivalent average force.

Worked examples

See the method in practice

01

Object moving left

A 2 kg object moving at −5 m/s has momentum −10 kg·m/s relative to an axis whose positive direction points right.

02

Reversal during a collision

A 2 kg object changing from +5 m/s to −1 m/s receives impulse −12 N·s. If the change takes 0.5 s, the average net force is −24 N.

Questions

Frequently asked

Are momentum and impulse the same quantity?

Momentum p describes a state of motion. Impulse J describes the effect of force over time and equals the change in momentum, not generally the momentum itself.

Why can the result be negative?

Momentum and impulse are vectors. In this one-dimensional calculator, the sign identifies direction relative to the positive axis you choose.

Why does a longer collision time reduce average force?

For the same momentum change, the average net-force projection is Δp/Δt. Increasing the stopping time reduces its magnitude.

Sources & review

Equations and examples are checked against the references below. Results are educational and should be independently verified for safety-critical work.

OpenStax University Physics — Linear Momentum OpenStax University Physics — Impulse and Collisions

Written by the STEM Hub editorial team · Reviewed August 11, 2026 · Review methodology