A metal disc spins on an axle inside a sealed, insulated container. The disc, axle, air and container are treated as a closed system.
Friction at the axle slows the disc. The kinetic energy store of the disc decreases by 3.2 kJ.
Explain what happens to the 3.2 kJ and why the total energy of the system does not decrease.
115 exam-style questions on Edexcel GCSE Physics 8.1 Energy transfers and work, covering 8.1.1 Energy stores and transfer diagrams, 8.1.2 Ways of changing a system's energy, and 8.1.3 Work done by forces. Each one has a worked solution and a mark scheme showing where the marks go.