4.8.1.1 System

Spec reference: 4.8.1 (subtopic).

What you need to know

• Systems
• Energy can be transferred in the following ways:
• mechanically – when work is done;
• electrically – when moving charge does work;
• heating – when energy is transferred from a hotter object to a colder
• object.
• Conservation of Energy
• Energy can never be created or destroyed, just transferred from one form

Self-assessment (checklist)

• I can name the celestial objects that make up our

Key steps (method)

• Identify what the question is testing and use the correct equation/definition.
• Show substitutions and units clearly.

Common mistakes

• Unit conversions, rearranging errors, or quoting a law without applying it.