Momentum Calculator

Motion and mass

What is momentum?

Linear momentum describes the quantity of motion carried by an object. It depends on both the object's mass and its velocity.

Formula

Momentum formula

• p is momentum in kilogram-meters per second.
• m is mass in kilograms.
• v is velocity in meters per second.

Worked example

A 12 kg object moves at 5 m/s

1. Write the formula: p = m × v.
2. Substitute the values: p = 12 × 5.
3. Calculate the momentum: p = 60 kg·m/s.

Rearranged equations

Solve for mass or velocity

Direction

Positive and negative momentum

Momentum is a vector quantity. Its sign represents direction relative to the positive axis selected for the problem. A negative velocity therefore produces negative momentum when mass is positive.

Stationary objects

When momentum equals zero

An object with zero velocity has zero momentum, regardless of its positive mass. Momentum may also become zero at the instant an object changes direction.

Units

Standard SI units

Use kilograms for mass and meters per second for velocity. Convert grams, kilometers per hour, and other units before entering values.

Calculation checks

Important input requirements

• Mass must be greater than zero.
• Velocity cannot be zero when solving for mass.
• Momentum and velocity must have matching signs when calculating mass.
• All entered values must be finite numbers.
• The calculator does not automatically convert units.

Questions and answers

Momentum calculator FAQ