Momentum Calculator
Calculate the momentum of an object based on its mass and velocity.
How to use the momentum calculator
- Enter the mass of the object in kilograms.
- Enter the velocity in meters per second.
- The result updates automatically as you type.
The formula for momentum
Worked example: an object of 5 kg moves at 10 m/s. Its momentum is 5 × 10 = 50 kg·m/s. An object of 50 kg at 1 m/s has exactly the same momentum — it is the product that counts, not how it is split between mass and velocity.
Momentum (p), sometimes also called linear momentum, is the mass (m) of an object multiplied by its velocity (v). It's measured in kg·m/s.
An important principle in physics is that momentum is conserved in a closed system — for example in collisions between two objects, the total momentum before and after the collision is the same. Momentum is also related to force through Δp = F × t: a force acting over a period of time changes an object's momentum.
Frequently asked questions
What's the difference between momentum and kinetic energy?
Momentum (p = m × v) is proportional to velocity, while kinetic energy (E = ½ × m × v²) increases with the square of velocity. They describe different properties of motion and are used for different purposes, including collision analysis.
What does it mean that momentum is "conserved"?
It means that in a closed system, with no external forces, the total momentum is the same before and after an event — for example a collision. This principle, conservation of momentum, is used to analyze impacts and collisions in physics.
How are force and momentum related?
A force acting over a period of time changes an object's momentum, expressed as Δp = F × t. This is often called the impulse of the force, and is another way of looking at Newton's second law.