1.1.3 Kinetic Energy

• Kinetic energy

  The energy an object possesses due to its motion
• Kinetic Energy Definition

  • Kinetic energy is the energy of a moving object
  • Any object that is in motion has kinetic energy
• Formula for Kinetic Energy

  Calculate using \(E_k = \frac{1}{2}mv^2\)
• Variables in Kinetic Energy Formula

  • \(E_k\)
  • \(m\)
  • \(v\)
• \(E_k\)

  Kinetic energy (measured in joules, J)
• \(m\)

  Mass of the object (measured in kilograms, kg)
• \(v\)

  Speed of the object (measured in meters per second, m/s)
• Dependence on Mass and Speed

  • Kinetic energy depends on mass and speed
  • Greater mass means more kinetic energy at the same speed
  • Kinetic energy increases with the square of the speed
• Kinetic energy is measured in joules (J)
• One joule is the energy transferred when a force of one newton moves an object one meter
• Examples of Kinetic Energy


  • A moving car
  • A rolling ball
  • An airplane in flight
• When a ball is dropped

  Gravitational potential energy is converted into kinetic energy
• As the roller coaster descends

  Gravitational potential energy is converted into kinetic energy
• Energy cannot be created or destroyed, only transferred from one form to another
• The energy an object gains or loses as it speeds up or slows down is balanced by energy transfers elsewhere
• Understanding kinetic energy helps in analyzing the motion of objects