impulse formulas and interpretation
Impulse measures the effect of force acting over a time interval.
Impulse equals the resulting change in linear momentum.
How to use the impulse calculator
- Choose a model: Select the relationship matching the problem.
- Choose the unknown: Select the quantity to calculate.
- Enter values: Enter all known values with matching units and signs.
- Calculate: Review the result, formula, units, and direction.
Formula and variables
For constant average force, impulse equals force times duration and equals momentum change.
J = FΔt = Δp- J — Impulse
- Change in momentum (N·s)
- F — Force
- Average net force (N)
- Δt — Time interval
- Force duration (s)
Force pulse example
A 10 N force acts for 3 seconds.
- Force
- 10 N
- Time
- 3 s
- J = 10 × 3
- J = 30 N·s
Result: Impulse is 30 N·s.
Momentum changes by 30 kg·m/s.
Understanding your results
Interpreting the result
Impulse direction follows the average net force.
Assumptions
- The selected equation represents the physical system.
- Inputs use a consistent reference direction.
- Values are converted through coherent SI units.
Limitations
- Vector components must be resolved along a common axis.
- External forces or energy losses are not added automatically.
- Results depend on the accuracy of entered measurements.
Common mistakes
- Mixing incompatible units.
- Dropping negative signs that represent direction.
- Using weight where mass is required.
- Entering a zero divisor.
Practical use cases
Physics problems
Check classroom, laboratory, and mechanics calculations.
Practical estimates
Estimate motion, forces, and energy for real systems.
Frequently asked questions
Can a result be negative?
Yes. For directional quantities, the sign indicates direction relative to the chosen positive axis.
Should I use SI units?
The interface can convert supported units, while the formulas are evaluated through coherent SI units.
Sources and review
- SI Brochure, 9th edition — BIPM. Accessed 2026-07-11.
- Special Publication 811 — NIST. Accessed 2026-07-11.
Reviewed 2026-07-11.