A student pushes a box to the right across a horizontal floor.
The Figure shows four forces, A, B, C and D, acting on the box.
Figure

Give the letter of the arrow that shows the normal contact force on the box.
Give the letters of all the contact forces shown in the Figure.
Explain why arrow B points to the left.
The weight of the box is 120 N.
Arrow C and arrow D are the same length.
Explain what this shows about the force represented by arrow D.
The floor is polished so that it is smoother. The student pushes the box with the same force.
State and explain what happens to the length of arrow B.
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.