An exercise machine has a pad pressed against the rim of a rotating flywheel. After the user stops pedalling, the flywheel slows down and the pad becomes warmer.
Which statement about the energy transfer is correct?
No work is done on the flywheel, because the pad stays still while it presses against the moving rim.
Friction does work as the rim moves past the pad, transferring energy from the flywheel's kinetic store to its gravitational potential energy store.
Friction does work as the rim moves past the pad, transferring energy from the flywheel's kinetic store to thermal energy stores.
Friction does work as the rim moves past the pad, transferring energy from thermal energy stores to the flywheel's kinetic store.
113 exam-style questions on AQA GCSE Physics 5.2 Work done and energy transfer, covering 5.2 Work done and energy transfer. Each one has a worked solution and a mark scheme showing where the marks go.