Energy

• Life is impossible without energy
• The Sun is the biggest natural source of energy to us
• Many of our energy sources are derived from the Sun
• An object that possesses energy can exert a force on another object
• When this happens, energy is transferred from the former to the latter
• The second object may move as it receives energy and therefore do some work
• The energy possessed by an object is measured in terms of its capacity of doing work
• The unit of energy is Joule (J)
• 1 kJ equals 1000 J
• Forms of energy

  • Mechanical energy (potential energy + kinetic energy)
  • Heat energy
  • Chemical energy
  • Electrical energy
  • Light energy