Kinetic Energy Calculator

Translational energy from mass and speed.

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Formula

KE = ½ m v²

Kinetic energy grows with the square of speed — doubling speed quadruples KE. Mass and speed must be in kg and m/s for joules.

Worked example

5 kg moving at 10 m/s has KE = ½ × 5 × 100 = 250 J.

Where this can give the wrong answer

  • Speed is entered as magnitude; direction does not affect scalar KE.
  • Rotational kinetic energy (spinning objects) needs Iω²/2, not this formula.
  • At everyday speeds relativistic corrections are negligible.

FAQ

Work-energy theorem shows energy scales with v² when force acts through distance under constant acceleration.