Kinetic Energy (HL IB Physics)

• Kinetic energy (E_k) is the energy an object has due to its translational motion (i.e. because it's moving)
  • The faster an object is moving, the greater its kinetic energy

• When an object is falling, it is gaining kinetic energy since it is accelerating under gravity
• This energy is transferred from the gravitational potential energy it is losing
• An object will maintain this kinetic energy unless its speed or mass changes

• Kinetic energy can be calculated using the following equation:

• Where:
  • E_k = kinetic energy (J)
  • m = mass (kg)
  • v = velocity (m s^–1)

Kinetic energy: The energy an object has when it is moving

• Another quantity that also depends on mass m and velocity v is momentum
• Therefore, kinetic energy can be written in terms of momentum p, using the equation

• Where:
  • p = momentum (kg m s^–1)

 

• This form is very useful in particle physics, when comparing the momentum and kinetic energy of a particle