Physics
Momentum and kinetic energy
Lets you convert between the two measures of motion. Because of the square, equal momenta do not mean equal energies unless the masses also match.
The Formula
KE = p^2 / (2 m)
Lets you convert between the two measures of motion. Because of the square, equal momenta do not mean equal energies unless the masses also match.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| p | Momentum | kilogram metres per second | The linear momentum of the object. |
| m | Mass | kilograms | The same mass used to define the momentum. |
| KE | Kinetic energy | joules | Always positive, because the momentum is squared. |
What Each Symbol Means
pkilogram metres per second
Momentum
The linear momentum of the object.
mkilograms
Mass
The same mass used to define the momentum.
KEjoules
Kinetic energy
Always positive, because the momentum is squared.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate momentum page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Momentum, filed under Science. Every number the guide produces comes from substituting into this one line.