Momentum Calculator
Calculate momentum, mass, or velocity using the formula p = m × v. Select the calculation mode below.
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What is Momentum?
Momentum is a fundamental concept in mechanics that describes the quantity of motion an object possesses. It is a vector quantity defined as the product of mass and velocity:
p = m × v
Where p is momentum in kg·m/s, m is mass in kg, and v is velocity in m/s. Momentum is conserved in all closed systems, making it one of the most important principles in physics for analyzing collisions, explosions, and interactions.
Common Momentum Reference Values
| Object / Event | Momentum (kg·m/s) |
|---|---|
| Person walking (70 kg at 1.4 m/s) | 98 |
| Car moving (1500 kg at 30 m/s) | 45,000 |
| Baseball pitch (0.145 kg at 45 m/s) | 6.53 |
| Bullet (0.01 kg at 400 m/s) | 4 |
| Train (500,000 kg at 20 m/s) | 10,000,000 |
| Earth orbiting Sun (6e24 kg at 30,000 m/s) | 180,000,000,000,000,000,000,000,000,000 |
| Truck (20,000 kg at 25 m/s) | 500,000 |
| Bicycle + rider (80 kg at 5 m/s) | 400 |
Related Calculators
Authoritative References
Frequently Asked Questions
What is momentum?
Momentum is a vector quantity that measures the motion of an object. It is defined as the product of mass and velocity: p = m × v. The SI unit of momentum is kg·m/s (kilogram-meters per second). Momentum is conserved in closed systems, meaning the total momentum before an interaction equals the total momentum after.
How do I calculate momentum?
Momentum is calculated by multiplying mass by velocity: p = m × v. For example, a 1500 kg car moving at 20 m/s has momentum of 30,000 kg·m/s. Doubling either mass or velocity doubles the momentum. Since momentum is a vector, direction matters
What is the law of conservation of momentum?
The law of conservation of momentum states that in a closed system with no external forces, the total momentum before an interaction equals the total momentum after. This principle is fundamental to understanding collisions, explosions, and rocket propulsion. For example, when two ice skaters push apart, they move in opposite directions with equal and opposite momentum.
What is impulse?
Impulse is the change in momentum of an object, equal to the force applied multiplied by the time interval: J = F × t = Δp. A large force applied briefly can produce the same impulse as a small force applied over a longer time. This is why airbags save lives — they increase the time of impact, reducing the force.
What is the difference between momentum and kinetic energy?
Momentum is a vector (p = mv) and is conserved in all collisions. Kinetic energy is a scalar (KE = ½mv²) and is only conserved in elastic collisions. In inelastic collisions, momentum is conserved but some kinetic energy is converted to heat, sound, or deformation.
How does momentum apply in sports?
In sports, momentum is crucial for understanding collisions and motion. In football, a heavier player moving slowly can have the same momentum as a lighter player moving fast. In billiards, the conservation of momentum and energy determines ball trajectories. In baseball, following through on a swing increases the time over which force is applied, increasing impulse and ball speed.