Momentum Calculator
Linear momentum (p = m × v) quantifies the inertial quantity of motion possessed by a moving object. Because momentum is conserved in all isolated physical systems, momentum calculations form the backbone of vehicle crash testing, ballistics engineering, particle physics, and sports biomechanics. This calculator computes total momentum, kinetic energy, and average peak impact forces during collisions.
Mass of the moving object in kilograms (kg)
Speed of translation in metres per second (m/s)
Time in seconds over which the object decelerates to rest upon impact
Quantity of motion in kg·m/s (or Newton-seconds, N·s)
How to Use This Calculator
- Enter the mass of the moving object in kilograms.
- Enter the travel velocity in metres per second (1 m/s = 3.6 km/h).
- Specify the deceleration impact duration in seconds (e.g., 0.1 s for a vehicle crumple zone).
- View the momentum, kinetic energy, and estimated collision force instantly.
Formula & Calculation Methodology
Linear momentum (p) is the product of mass and velocity. The impulse-momentum theorem states that total impulse (J) transferred during an impact equals the change in momentum (Δp), producing an average force of F = Δp / Δt.
Worked Example
A 1,200 kg car traveling at 15 m/s (54 km/h) coming to a stop against a barrier in 0.15 seconds
Frequently Asked Questions
Why are crumple zones so important in automotive safety?↓
According to the impulse-momentum theorem (F = Δp / Δt), lengthening the collision duration Δt via controlled metal crumpling drastically decreases the peak deceleration force F exerted on human passengers.
How does momentum differ from kinetic energy?↓
Momentum is a vector quantity proportional to velocity (m × v) that is always conserved in both elastic and inelastic collisions. Kinetic energy is a scalar proportional to velocity squared (0.5 × m × v²) and is partially converted to heat/deformation in inelastic collisions.
What is the Law of Conservation of Momentum?↓
In any closed isolated system where no external net forces act, the total vector momentum before a collision equals the total vector momentum after the collision (Σ p_initial = Σ p_final).
What limitation exists when modeling non-constant impact forces?↓
Real collisions do not produce uniform rectangular force profiles. The impact force calculated here represents the average time-integrated force; peak instantaneous force during maximum structural deformation is typically 1.5 to 2.5 times higher.
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Source Citation & Disclaimer
Informational tool only; not licensed tax, legal, or financial advice.