aqa gcse physics topic 1: energy

• Energy is never created or destroyed, only transferred between different forms and objects
• Different forms of energy include:

  • Thermal or internal energy: heat energy trapped within an object
  • Kinetic energy: associated with the movement or motion of an object
  • Gravitational potential energy: energy due to an object's position in a gravitational field
  • Elastic potential energy: energy held in a stretched spring
  • Chemical energy: held in chemical bonds
  • Magnetic energy: holds magnets together
  • Electrostatic energy: gives shocks when touching certain objects
  • Nuclear energy: obtained from breaking atoms apart
• Energy can be transferred between different energy stores mechanically, electrically, by heating, or by radiation like light or sound waves
• In a system, energy can be transferred between objects or between different forms; in an open system, energy can exchange with the outside world, while in a closed system, neither matter nor energy can enter or leave
• Work done is another way of saying energy transferred, with two main types:

  • Mechanical work done: using a force to move an object
  • Electrical work done: done when current flows, overcoming resistance in wires
• Kinetic energy is the energy that an object possesses due to its motion
• The amount of kinetic energy an object has depends on its speed and mass
• For speed, the faster an object moves, the more kinetic energy it will have
• For mass, as long as speed is equal, the more mass an object has, the more kinetic energy it will have
• The equation to calculate kinetic energy is: E_k = 1/2 * m * v^2, where E_k is kinetic energy, m is mass in kilograms, and v is velocity in meters per second
• Example calculation for a plane with 20,000 kg mass and speed of 5 m/s: 0.5 * 20,000 * 5^2 = 250,000 joules (250 kilojoules)
• Example calculation for a particle with 0.0001 kg mass and speed of 4000 m/s: 0.5 * 0.0001 * 4000^2 = 800 joules (0.8 kilojoules)