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How to use this calculator
Choose the formula (if there is more than one), choose what you want to find, then fill in the other values using the units shown. The calculator rearranges the formula, puts your numbers in, and shows every step.
How it's calculated
Momentum p = mv. Impulse: Ft = m(v − u). In a collision with no outside forces, total momentum stays the same: m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂.
Worked example
A 4 kg ball moving at 6 m/s has momentum 4 × 6 = 24 kg m/s.
Frequently asked questions
What is impulse?
Force multiplied by the time it acts. It equals the change in momentum.
How do I show direction?
Use positive for one direction and negative for the opposite one.
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Last updated October 2026. Results are for learning and guidance; always check important work. Calculations run in your browser and are not stored.