Derivation of KE = 1/2mv2
- Kinetic energy is energy an object has due to its motion (or velocity)
- A force can make an object accelerate; work is done by the force and energy is transferred to the object
- Using this concept of work done and an equation of motion, the extra work done due to an object’s speed can be derived
- The derivation for this equation is shown below:
Kinetic Energy
- Kinetic energy is energy an object has due to its motion (or velocity)
- The faster an object is moving, the greater its kinetic energy
- When an object is falling, it is gaining kinetic energy since it is gaining speed. This energy transferred from the gravitational potential energy it is losing
- An object will maintain this kinetic energy unless its speed changes
Equation for Kinetic energy
Exam Tip
When using the kinetic energy equation, note that only the speed is squared, not the mass or the ½.
If a question asks about the ‘loss of kinetic energy’, remember not to include a negative sign since energy is a scalar quantity.