Kinetic Energy Calculator
Calculate kinetic energy using KE = 1/2mv^2. Input mass (kg) and velocity (m/s) to get kinetic energy in joules, electronvolts, and calories, plus momentum and de Broglie wavelength.
About This Calculator
This Kinetic Energy Calculator computes the energy of motion using the physics formula KE = 1/2 x m x v^2. Enter the mass in kilograms and velocity in meters per second to instantly calculate kinetic energy in joules, electronvolts (eV), and calories (cal). The calculator also computes momentum p = mv and the de Broglie wavelength lambda = h/p.
Results are displayed across six cards with a chart showing how kinetic energy scales with velocity (quadratic relationship) and a breakdown table showing the individual components of the calculation.
Regional Notes
All regions (SI units): This calculator uses the International System of Units (kg, m/s) which is standard in physics worldwide. The United States uses SI for scientific calculations, so defaults are identical across all regions.
Conversions: 1 eV = 1.602 × 10⁻¹⁹ J, 1 cal = 4.184 J. Momentum is given in kg·m/s and velocity in km/h for practical reference.
Applications
Useful for physics students, engineers, and researchers studying mechanics, thermodynamics, quantum mechanics (de Broglie wavelength), and collision analysis.
Frequently Asked Questions
What is kinetic energy and how is it calculated?
Kinetic energy is the energy of motion, calculated as KE = 1/2 x m x v^2 where m is mass in kilograms and v is velocity in meters per second. A 70 kg person running at 10 m/s has 3,500 J of kinetic energy.
What is the difference between classical and relativistic kinetic energy?
Classical KE = 1/2mv^2 is accurate for speeds much less than the speed of light (v ≪ c). At relativistic speeds, KE = (gamma - 1)mc^2 where gamma = 1/sqrt(1 - v^2/c^2). This calculator uses the classical formula, suitable for everyday speeds.
How do you convert kinetic energy to different units?
Kinetic energy in joules can be converted to electronvolts (1 eV = 1.602 × 10⁻¹⁹ J) and calories (1 cal = 4.184 J). This calculator shows all three units simultaneously for convenience.
What units are used for mass and velocity?
This calculator uses SI units: kilograms (kg) for mass and meters per second (m/s) for velocity. Results include kinetic energy in joules, electronvolts, and calories, momentum in kg·m/s, and de Broglie wavelength in meters.
How is momentum related to kinetic energy?
Momentum p = mv is linearly related to velocity, while kinetic energy KE = 1/2mv^2 is quadratic. They are related by KE = p^2/(2m). This calculator computes both values for comparison.
What is the de Broglie wavelength?
The de Broglie wavelength lambda = h/p relates a particle's momentum to its quantum wavelength, where h = 6.626 × 10⁻³⁴ J·s is Planck's constant. Every moving object has a de Broglie wavelength, though it is only measurable for microscopic particles.
How accurate are the results?
Results are computed to 2 decimal places for joules, momentum, and km/h. Electronvolts and de Broglie wavelength use exponential notation for precision across many orders of magnitude. All formulas use standard physical constants.