Physics (AS & A Level) · Oct / Nov 2016 · Paper 11 · Question 12

A box is shown resting on the ground. Newton's third law implies that four forces of equal magnitude are involved. These forces are labelled P, Q, R and S. Forces P and Q act on the box. Forces R and S act on the Earth. For clarity, the forces are shown slightly separated. Which statement about the forces is correct?

1. AP is the equal and opposite force to Q and both are forces of contact.
2. BQ is the equal and opposite force to P and both are gravitational forces.
3. CR is the equal and opposite force to S and both are forces of contact.
4. DS is the equal and opposite force to Q and both are gravitational forces.

As printed in the paper