Momentum Calculator (p = m·v)

Compute linear momentum from mass and velocity. Result in kg·m/s, with a comparison to a typical small car at highway speed.

Inputs

In kilograms (kg). 0.145 kg ≈ a baseball.

In metres per second. 40 m/s ≈ 90 mph fastball.

Result

Momentum
5.800 kg·m/s
  • In g·cm/s (CGS)580,000 g·cm/s
  • Vs a 1500 kg car at 100 km/hReference car momentum ≈ 41 670 kg·m/s.0.014%

Step-by-step

  1. p = m × v.
  2. p = 0.145 kg × 40 m/s = 5.800 kg·m/s.

How to use this calculator

  • Enter the mass of the object in kilograms.
  • Enter the velocity in metres per second.
  • Read momentum in kg·m/s. The breakdown compares to a small car at 100 km/h.

About this calculator

Momentum is mass in motion: the product of an object's mass and its velocity, p = m·v. It is a vector quantity (direction matters) and is conserved in any closed system — that is the principle behind every collision analysis and rocket-propulsion problem. The total momentum before equals the total momentum after, regardless of whether the collision is elastic or inelastic. Impulse (force × time) equals change in momentum, which is why crumple zones and airbags work: they extend the time of a collision, reducing the peak force for the same Δp. Momentum is measured in kg·m/s; the CGS unit g·cm/s is occasionally used in particle physics.

Frequently asked

No — inertia is just mass (the resistance to a change in motion). Momentum is mass × velocity, so a stationary object has inertia but zero momentum.

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