Momentum Calculator
Free momentum calculator — p = m·v in kg·m/s; solve for momentum, mass, or velocity, with an animated illustration.
Everyday Uses
Physics homework
Compute p = m·v and explore conservation of momentum in collisions.
Sports & games
Understand why a fast, heavy hit transfers more momentum in pool, football, or boxing.
Crash physics
Link momentum change to impulse — the idea behind airbags and crumple zones.
Rockets
See how expelling mass backward drives a rocket forward by conserving momentum.
Frequently Asked Questions
What is the formula for momentum?
Momentum is p = m × v — mass in kilograms times velocity in m/s — measured in kg·m/s. A 2 kg ball moving at 10 m/s has momentum p = 20 kg·m/s. Momentum is a vector, so its direction matters. Rearranged, m = p ÷ v and v = p ÷ m.
What is the conservation of momentum?
In a closed system with no external forces, total momentum stays constant. In a collision, the combined momentum of all objects before equals the combined momentum after. This is why a cue ball transfers its momentum to the balls it strikes, and why a gun recoils when a bullet is fired.
How are momentum and impulse related?
Impulse equals the change in momentum: J = Δp = F × Δt. A force applied over time changes an object's momentum. This is why airbags help — by extending the stopping time, they reduce the force needed to change your momentum in a crash.