A mechanical timer contains a spring, gears and an axle.
The table gives observations made while the timer operates.
| Observation | Energy store indicated by the observation |
|---|---|
| The spring is twisted before the timer is released. | |
| The gears are rotating. | |
| The temperature of the axle has increased. |
Complete the final column of the table.
During one interval, the energy held because the spring is twisted decreases by 24 J.
The energy held because the gears are rotating increases by 9 J.
The timer and its surroundings are treated as a closed system.
Calculate the increase in energy held because the temperatures of the timer and its surroundings rise.
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.