2. Kinetic Energy

1. What is Kinetic Energy?

Kinetic energy is the energy an object possesses due to its motion. Anything that is moving—from a tiny particle to a massive airplane—has energy in its kinetic energy store.

2. Factors Affecting Kinetic Energy

The amount of kinetic energy an object has depends on two variables:

  • Mass: The greater the mass of an object, the more kinetic energy it has (assuming speed stays the same).

  • Speed (Velocity): The faster an object moves, the more kinetic energy it has.

3. The Kinetic Energy Equation

To calculate the exact amount of energy, use the following formula:

KE = ½ mv²

  • KE: Kinetic Energy, measured in Joules (J).

  • m: Mass, measured in kilograms (kg).

  • v: Velocity (speed), measured in meters per second (m/s).

4. Key Calculation Tips

  • Units Matter: Always ensure mass is in kg and speed is in m/s before plugging them into the formula.

    • To convert grams to kg: divide by 1,000.

    • To convert tons to kg: multiply by 1,000.

  • Squaring the Velocity: In the equation, only the velocity is squared, not the mass or the $1/2$.

  • Kilojoules: Results are often large, so you may need to convert Joules to kilojoules (kJ) by dividing by 1,000 (1 kJ = 1,000 J).