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physics

Momentum Calculator

Calculate linear momentum (p = mv), the product of mass and velocity. Momentum is conserved in collisions and fundamental to mechanics.

Reviewed by Christopher FloiedPublished Updated

This free online momentum calculator provides instant results with no signup required. All calculations run directly in your browser — your data is never sent to a server. Enter your values below and see results update in real time as you type. Perfect for everyday calculations, homework, or professional use.

Minimum: 0

Results

Momentum

50 kg·m/s

How to Use This Calculator

1

Enter your input values

Fill in all required input fields for the Momentum Calculator. Most fields include unit selectors so you can work in your preferred unit system — metric or imperial, whichever matches your problem.

2

Review your inputs

Double-check that all values are correct and that you have selected the right units for each field. Incorrect units are the most common source of calculation errors and can produce results that are off by factors of 2, 10, or more.

3

Read the results

The Momentum Calculator instantly computes the output and displays results with units clearly labeled. All calculations happen in your browser — no loading time and no data sent to a server.

4

Explore parameter sensitivity

Try adjusting individual input values to see how the output changes. This is a quick and effective way to develop intuition about how different parameters influence the result and to identify which inputs have the largest effect.

When to Use This Calculator

  • Use the Momentum Calculator when you need accurate results quickly without the risk of manual computation errors or unit conversion mistakes.
  • Use it to verify calculations made by hand or in spreadsheets — an independent check can catch errors before they lead to costly decisions.
  • Use it to explore how changing input parameters affects the output — a quick way to develop intuition and identify the most influential variables.
  • Use it when collaborating with others to ensure everyone is working from the same numbers and applying the same assumptions.

About Momentum Calculator

The Momentum Calculator computes linear momentum — the product of mass and velocity. Momentum is a vector quantity that captures how hard it is to stop a moving object. A heavy truck moving slowly can have the same momentum as a light bullet moving fast. Momentum is conserved in isolated systems — this principle underlies rocket propulsion, billiard ball collisions, and car crash physics.

The Math Behind It

Linear momentum (p) is fundamental in physics. Its importance stems from conservation: in a closed system, total momentum before and after any interaction remains constant. **p = mv** is deceptively simple. Its power comes from: 1. **Newton's Second Law**: F = dp/dt. Force is the rate of change of momentum. 2. **Conservation**: In any collision or explosion where external forces are negligible, Σp_before = Σp_after. This is why guns recoil, rockets work, and billiard balls exchange momentum predictably. 3. **Impulse-momentum theorem**: J = F·Δt = Δp. A small force over long time can produce the same momentum change as a large force over short time. This is why airbags work. **Examples**: - Bullet: ~5 kg·m/s - Baseball pitch: ~6 kg·m/s - Car at 60 mph: ~30,000 kg·m/s

Formula Reference

Linear Momentum

p = mv

Variables: m = mass (kg), v = velocity (m/s)

Worked Examples

Example 1: Car Momentum

1500 kg car at 20 m/s

Step 1:p = 1500 × 20 = 30,000 kg·m/s

Momentum of 30,000 kg·m/s.

Example 2: Bullet vs Football

0.01 kg bullet at 400 m/s vs 0.4 kg football at 20 m/s

Step 1:Bullet: 0.01 × 400 = 4
Step 2:Football: 0.4 × 20 = 8

Football has more momentum despite moving slower.

Common Mistakes & Tips

  • !Confusing momentum (mv) with kinetic energy (½mv²).
  • !Forgetting momentum is a vector — direction matters.

Related Concepts

Used in These Calculators

Calculators that build on or apply the concepts from this page:

Frequently Asked Questions

Momentum vs kinetic energy?

Momentum (p = mv) is linear in velocity and conserved in collisions. KE (½mv²) is quadratic and may not be conserved (inelastic collisions).

Is momentum always conserved?

Yes, in any isolated system with no external forces.