Physics Formula
Kinetic Energy Formula
Calculates energy due to an object's motion.
Formula Summary
Kinetic Energy
Calculates energy due to an object's motion.
- Category
- Physics
- Equation
- Eₖ = ½mv²
- Calculator
- Use Kinetic Energy Calculator →
Equation
Eₖ = ½mv²
Variables
- Eₖ = kinetic energy
- m = mass
- v = velocity
Units
- Kinetic Energy: Joules (J)
- Mass: kilogram (kg)
- Velocity: meters per second (m/s)
When To Use This Formula
Use this formula when calculating the energy an object has because of its motion. It is commonly used in mechanics, collisions, and energy analysis.
Rearranged Equations
- m = 2Eₖ / v²
- v = √(2Eₖ / m)
How to Use This Formula
- Identify the known values from the problem statement.
- Convert all values into compatible units.
- Substitute the values into the equation and calculate the result.
- Check that the final answer has the correct unit and meaning.
Explanation
Kinetic energy is the energy an object possesses because of its motion. It depends on the object's mass and the square of its velocity.
Worked Example
A 2 kg object moving at 5 m/s has kinetic energy of ½ × 2 × 5² = 25 J.
Common Mistakes
- Forgetting that velocity must be squared.
- Using mass in incorrect units.
- Confusing kinetic energy with total mechanical energy.
Applications
- Vehicle motion and collision analysis.
- Mechanical engineering calculations.
- Studying energy changes in moving systems.