Equations · Physics
Kinetic energy
The energy a body has because it moves: half its mass times its speed squared.
Eₖ = ½mv²
Aethel says
E sub k equals one half m v squared
What it says
Because speed is squared, doubling the speed quadruples the energy, which is why stopping distances grow so quickly with speed.
This is the form for speeds well below the speed of light.
Symbol by symbol
| Symbol | Say it | Means |
|---|---|---|
| Eₖ | E sub k | the kinetic energy, in joules |
| m | m | the mass |
| v | v | the speed |
Where you meet it
Mechanics courses and engineering.
Questions
How do you say Kinetic energy out loud?
Eₖ = ½mv² is read: “E sub k equals one half m v squared.” That is exactly what Aethel says when it meets the formula in a book.
What does Eₖ mean in Kinetic energy?
Eₖ (said “E sub k”) is the kinetic energy, in joules.
What does m mean in Kinetic energy?
m (said “m”) is the mass.
Can I listen to the equations in my own textbook like this?
Yes. Upload a PDF, EPUB or text file and Aethel reads it aloud with every equation spoken as maths, the way it reads this one, and highlights each sentence as it goes. You can start free.