Asian Sciences Olympiad 2015 — Division M, Level 3 (Years 7–9) Question 11

Question 11

A man of weight W is standing on the ground. Which of the followings forms an action-and-reaction pair with W?

1. The reaction force acting on the man by the ground.
2. The force acting on the ground by the man.
3. The gravitational force acting on the man by the Earth.
4. The gravitational force acting on the Earth by the man