Momentum
Definition
The product of an object's mass and velocity (p = mv), representing the quantity of motion. Measured in kg·m/s.
Why is Momentum Important?
Momentum is a core physics concept that describes the fundamental behavior of matter and energy. Understanding this principle enables engineers, students, and scientists to design better systems, solve real-world problems, and predict physical phenomena with precision.
Our physics calculators make it easy to compute values related to this concept, bridging the gap between theoretical understanding and practical application in engineering, education, and research.
What is Momentum?
Momentum (p) is the product of an object's mass and velocity: p = mv. It represents the quantity of motion an object has. A heavier object or a faster object has more momentum. Momentum is a vector quantity — it has both magnitude and direction.
Key Momentum Principles
| Principle | Formula | Meaning |
|---|---|---|
| Momentum | p = mv | Mass × velocity |
| Impulse | J = FΔt = Δp | Force × time = change in momentum |
| Conservation of Momentum | p₁ + p₂ = p₁' + p₂' | Total momentum before = after (closed system) |
Momentum Comparisons
| Object | Mass | Speed | Momentum (kg·m/s) |
|---|---|---|---|
| Tennis ball serve | 0.058 kg | 60 m/s (134 mph) | 3.5 |
| Baseball pitch | 0.145 kg | 42 m/s (95 mph) | 6.1 |
| Running person | 75 kg | 3 m/s (6.7 mph) | 225 |
| Car at highway speed | 1,500 kg | 30 m/s (67 mph) | 45,000 |
| 18-wheeler truck | 36,000 kg | 30 m/s (67 mph) | 1,080,000 |
Types of Collisions
| Type | Momentum | Kinetic Energy | Example |
|---|---|---|---|
| Elastic | Conserved ✓ | Conserved ✓ | Billiard balls, atomic particles |
| Inelastic | Conserved ✓ | Not conserved ✗ | Car crash, catching a ball |
| Perfectly Inelastic | Conserved ✓ | Maximum loss | Objects stick together after collision |