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Kinetic Energy calculator
Kinetic energy is the energy of motion. Enter any two of energy, mass and velocity to find the third.
Kinetic Energy
KE = ½mv² · Motion · Energy · Velocity
KE = ½ × m × v² | Energy in Joules
About the Kinetic Energy calculator
Kinetic energy is the energy of motion. Enter any two of energy, mass and velocity to find the third.
How to use the Kinetic Energy calculator
- Choose what to solve for under Solve For: KE, m or v.
- Enter the Mass (kg) and Velocity (m/s) (or the energy).
- Press Calculate.
Formula and method
KE = ½ × m × v². Energy is measured in joules.
Worked example
A 1,000 kg car moving at 20 m/s has 200,000 J (200 kJ) of kinetic energy. Doubling the speed quadruples the energy.
Doubling speed. A 1,000 kg car at 10 m/s has ½ × 1,000 × 100 = 50,000 J. At 20 m/s the energy is 200,000 J, four times as much.
When to use the Kinetic Energy calculator
- Working out the energy of a moving car, ball or projectile.
- Understanding why speed matters so much in a collision.
- Solving mechanics problems.
Common mistakes to avoid
- Forgetting that velocity is squared, so doubling speed quadruples the energy.
- Using km/h instead of m/s in the formula.
Tips
- Velocity is squared, so speed has a large effect. This is why high-speed crashes are so severe.
- Convert km/h to m/s by dividing by 3.6.
Frequently asked questions
Why is velocity squared?
Because the work needed to reach a speed grows with the square of that speed.
What is the unit of kinetic energy?
The joule (J).