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How to Calculate Kinetic Energy

What is Kinetic Energy?

Kinetic energy is the energy possessed by an object due to its motion. It depends on both mass and the square of velocity — doubling speed quadruples kinetic energy, while doubling mass only doubles it. KE is the work-energy theorem in action: the net work done on an object equals the change in its kinetic energy.

Formula

KE = ½mv² (joules, J)
KE
½mv² (joules — ½mv² (joules
J
J value — Variable used in the calculation

Step-by-Step Guide

  1. 1KE = ½mv² (joules, J)
  2. 2m = mass in kg, v = velocity in m/s
  3. 3Momentum p = mv (kg⋅m/s) — conserved in collisions
  4. 4Work done to bring to rest = KE (e.g. braking distance calculation)
  5. 5KE is scalar (no direction); momentum is a vector

Worked Examples

Input
70 kg person running at 10 m/s (36 km/h)
Result
KE = ½ × 70 × 100 = 3,500 J
Equivalent to lifting ~350 kg by 1 metre
Input
1,500 kg car at 30 m/s (108 km/h)
Result
KE = 675,000 J = 675 kJ
Explains why speeding is so dangerous
Input
0.006 kg bullet at 900 m/s
Result
KE = 2,430 J — more than a running person

Frequently Asked Questions

What is Kinetic Energy Calc?

Kinetic energy is the energy possessed by an object due to its motion. It depends on both mass and the square of velocity — doubling speed quadruples kinetic energy, while doubling mass only doubles it

How accurate is the Kinetic Energy Calc calculator?

The calculator uses the standard published formula for kinetic energy calc. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

What units does the Kinetic Energy Calc calculator use?

This calculator works with kilograms, inches, watts. You can enter values in the units shown — the calculator handles all conversions internally.

What formula does the Kinetic Energy Calc calculator use?

The core formula is: KE = ½mv² (joules, J). Each step in the calculation is shown so you can verify the result manually.

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