What is impulse in physics?

Impulse (J) is the product of a net force and the time interval over which it acts: J = F × Δt. It equals the change in momentum of an object (Δp = m × Δv), which is the impulse-momentum theorem. The SI unit is the newton-second (N·s), equivalent to kg·m/s.

What is the difference between impulse and momentum?

Momentum (p = mv) describes the quantity of motion an object has at a given instant. Impulse (J = FΔt) describes the change in that momentum caused by a force over time. Impulse equals the change in momentum: J = Δp.

Why is a longer contact time safer in collisions?

Because J = F × Δt and impulse (change in momentum) is fixed by the collision speed and mass, a longer contact time Δt means a smaller average force F. Airbags and crumple zones extend contact time to reduce peak impact force.

What units does this calculator support?

Force: N, kN, lbf. Time: seconds (s), milliseconds (ms), minutes (min). Mass: kg, g, lb. Velocity: m/s, km/h, mph, ft/s. Impulse output is shown in N·s, kN·s, lbf·s, and kg·m/s.

Can this calculator solve for force or time instead of impulse?

Yes. In "Force × Time" mode you can solve for J (impulse), F (force), or Δt (time). In "Momentum Change" mode you can solve for J, mass (m), or velocity change (Δv).

Impulse Calculator

Name: Impulse Calculator
Availability: InStock
Author: Nham Vu

Calculate impulse using J = F × t or J = m × Δv, with support for multiple units and solve-for-any-unknown mode.

Impulse Calculator

Mode

Solve for

Force

Time

Enter two known values on the left to compute impulse.

J = F × Δt • J = m × Δv

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Summary

Calculate impulse using J = F × t or J = m × Δv, with support for multiple units and solve-for-any-unknown mode.

How it works

Choose a mode: "Force × Time" (J = F × t) or "Momentum Change" (J = m × Δv).
Select what you want to solve for using the "Solve for" buttons.
Enter the two known values and select their units from the dropdowns.
The result appears instantly with cross-unit conversions and a worked example.
Click any conversion card or the "Copy" button to copy the value to your clipboard.

Use cases

Calculate the impulse delivered by a rocket thruster over a burn time.
Determine the force of impact during a collision given contact time.
Find the momentum change experienced by a vehicle during braking.
Solve physics homework problems on the impulse-momentum theorem.
Compute the contact time of a bat hitting a ball from known force and impulse.
Verify safety engineering calculations for airbag deployment timing.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu