During autumn, rail operators often introduce a temporary reduced speed limit on sections of track affected by fallen leaves. When crushed by heavy train wheels, the leaves form a thin, slippery layer of mulch on the steel rails.
Explain, in terms of forces and stopping distances, why trains must operate at a lower speed under these conditions.
39 exam-style questions on Edexcel GCSE Physics 2.5 Stopping and braking distances. Each one has a worked solution and a mark scheme showing where the marks go.