Kinetic energy is the energy an object has because it is moving. It depends on mass and, much more strongly, on speed: KE = ½mv². This kinetic energy calculator accepts speed in m/s, km/h or mph and converts it to m/s for you.
Because speed is squared, a car at 100 km/h has about four times the kinetic energy it has at 50 km/h, and needs about four times the distance to stop.
| Mass (m) | 1,000 kg |
| Speed (v) | 72 |
| Speed unit | km/h |
| Kinetic energy (J) | 200,000 |
| Kinetic energy (kJ) | 200 |
| Speed (m/s) | 20 |
| Momentum (kg·m/s) | 20,000 |
A 1,000 kg car at 72 km/h (20 m/s) has 200,000 J of kinetic energy.
Try this example →| Mass (m) | 0.16 kg |
| Speed (v) | 40 |
| Speed unit | m/s |
| Kinetic energy (J) | 128 |
| Kinetic energy (kJ) | 0.128 |
| Speed (m/s) | 40 |
| Momentum (kg·m/s) | 6.4 |
The ball carries 128 J.
Try this example →The work done by the net force on an object equals its change in kinetic energy: W = ½mv² − ½mu². Brakes remove a car's kinetic energy by doing negative work, turning it into heat.
KE = ½mv², where m is mass in kg and v is speed in m/s. The answer is in joules.
It becomes four times as large, because it depends on v².
No. Mass is positive and v² is never negative.
KE = p² ÷ 2m, where p = mv is the momentum.