Momentum Calculator: p = mv With Units
This momentum calculator solves the linear momentum formula p = m × v for any one of the three values. Pick what you want to find, enter the other two, and choose units such as pounds or kilograms for mass and mph, feet per second, km/h or meters per second for velocity. Momentum is shown in kilogram-meters per second and in pound-feet per second, and the tool also gives the kinetic energy of the object, which is a handy check in collision problems. It is built for physics homework, sports science questions and quick engineering estimates.
Momentum Calculator
Solve p = mv for momentum, mass or velocity in US or SI units.
How to use the Momentum Calculator
- Choose to solve for momentum, mass or velocity.
- Enter the two known values and their units.
- Read the answer in SI and US units, plus kinetic energy.
Momentum formula
p = m × v. Kinetic energy KE = ½ m v² = p² ÷ (2m).
Features
- Solves p = mv three ways
- Mass in kg, lb or g
- Velocity in m/s, ft/s, mph or km/h
- kg·m/s and lb·ft/s output
- Kinetic energy shown
- Copy and print
Frequently asked questions
What is the formula for momentum?
Momentum p = mass × velocity. A 1,000 kg car at 20 m/s has 20,000 kg·m/s of momentum.
What are the units of momentum?
In SI units, kilogram-meters per second (kg·m/s), which equals newton-seconds. In US units, pound-feet per second.
Is momentum a vector?
Yes. It has the same direction as the velocity, so objects moving in opposite directions have opposite signs.
How is momentum different from kinetic energy?
Momentum is m × v and is always conserved in collisions. Kinetic energy is ½ m v² and can be lost to heat and sound.
How do I find velocity from momentum?
Divide momentum by mass: v = p ÷ m.