Impulse Calculator
Calculate impulse (change in momentum) and average force from mass, velocity change and time interval.
How to use the impulse calculator
- Enter the mass of the object.
- Enter the initial and final velocity.
- Enter the time interval the velocity change happened over.
- The impulse and average force update automatically.
What is impulse?
Impulse is the change in momentum of an object, and relates to the force acting and how long it acts: J = F × Δt = Δp = m × Δv. The impulse-momentum theorem states that the impulse applied to an object equals the change in the object's momentum. This calculator computes the impulse from the velocity change, and the average force that must have acted over the given time interval.
Frequently asked questions
What is the relationship between impulse and momentum?
Impulse is by definition the change in momentum. If an object of mass m changes velocity from v₁ to v₂, the change in momentum (and thus the impulse) equals m × (v₂ − v₁).
Why do airbags and protective gear use the impulse principle?
Because the impulse (velocity change) in a collision is fixed by physics, but the force depends on how long the collision takes. By extending the collision time (e.g. with an airbag that deforms), the force acting on the body is reduced, since J = F × Δt is constant.
What's the difference between impulse and force?
Force (measured in newtons) is an instantaneous effect. Impulse (measured in kg·m/s, equivalent to N·s) is the effect of a force acting over a time period — it's the force multiplied by how long it acts.