Kinetic vs. Potential Energy: What's the Difference?
Both are forms of mechanical energy, and the difference is motion. Kinetic energy is the energy an object has because it's moving. Potential energy is stored energy an object has because of its position or state, ready to become motion. A ball at the top of a hill has potential energy; rolling down, that becomes kinetic energy.
See the difference, explained visually.
Watch a 2-minute animated lesson comparing kinetic energy and potential energy.
At a glance
| Kinetic Energy | Potential Energy | |
|---|---|---|
| What it is | Energy of motion | Stored energy (position/state) |
| When | While the object is moving | Before it moves — waiting to release |
| Depends on | Mass and speed | Position, height, or configuration |
| Example | A rolling ball, flowing water | A ball on a shelf, a stretched spring |
| Formula | KE = ½mv² | PE = mgh (for height) |
Which should you use?
Kinetic Energy
It's kinetic energy whenever something is actually moving — a car driving, water flowing, or a thrown ball in flight. The faster and heavier it is, the more it has.
Potential Energy
It's potential energy when energy is stored and ready — a boulder at a cliff edge, a drawn bow, or water held behind a dam. Release it and it converts to kinetic energy.
Frequently asked questions
- Can energy switch between the two?
- Constantly. A falling object converts potential energy into kinetic energy; a ball thrown upward does the reverse. The total (in an ideal system) stays the same.
- Is a stretched rubber band kinetic or potential?
- Potential — specifically elastic potential energy. The moment you let go, that stored energy turns into the kinetic energy of motion.
- What decides how much kinetic energy something has?
- Its mass and speed: KE = ½mv². Speed matters most because it's squared — doubling the speed quadruples the kinetic energy.