A cleaner presses a sponge vertically upwards against the underside of a horizontal shelf.
Which statement describes the normal contact force that the sponge experiences at the shelf?
The shelf pushes vertically upwards on the sponge.
The shelf pushes vertically downwards on the sponge.
The sponge pushes vertically downwards on the shelf.
The sponge pushes vertically upwards on the shelf.
93 exam-style questions on Edexcel GCSE Physics 9.1 Forces and vectors, covering 9.1.1 Interactions and types of force, 9.1.2 Vector and scalar quantities, and 9.1.3 Vector diagrams and free body diagrams. Each one has a worked solution and a mark scheme showing where the marks go.