In physics, which of these is the meaning of the word system?
an object or a group of objects
a force acting on a single object
a store of energy inside an object
a transfer of energy by heating
40 exam-style questions on AQA GCSE Physics 1.1 Energy changes in a system, and the ways energy is stored before and after such changes, covering 1.1.1 Energy stores and systems, 1.1.2 Changes in energy, 1.1.3 Energy changes in systems, and 1.1.4 Power. Each one has a worked solution and a mark scheme showing where the marks go.